Merge tag 'Second_Life_Release#d9e55c44-Second_Life_Release#d9e55c4-2025.04' into 2025.04

56 files changed, 1534 insertions, 444 deletions

diff --git a/.github/workflows/.gitattributes b/.github/workflows/.gitattributes
new file mode 100644
index 0000000000..6dc1cca42a
--- /dev/null
+++ b/.github/workflows/.gitattributes
@@ -0,0 +1 @@
+qatest.yaml -text eol=crlf
diff --git a/.github/workflows/qatest.yaml b/.github/workflows/qatest.yaml
index 7f3a5242e9..4892cfaae3 100644
--- a/.github/workflows/qatest.yaml
+++ b/.github/workflows/qatest.yaml
@@ -1,4 +1,7 @@
 name: Run QA Test # Runs automated tests on a self-hosted QA machine

+permissions:

+  contents: read

+  #pull-requests: write # maybe need to re-add this later

 

 on:

   workflow_run:

@@ -15,11 +18,14 @@ jobs:
     runs-on: ubuntu-latest

     steps:

       - name: Debug Workflow Variables

+        env:

+          HEAD_BRANCH: ${{ github.event.workflow_run.head_branch }}

+          HEAD_COMMIT_MSG: ${{ github.event.workflow_run.head_commit.message }}

         run: |

           echo "Workflow Conclusion: ${{ github.event.workflow_run.conclusion }}"

-          echo "Workflow Head Branch: ${{ github.event.workflow_run.head_branch }}"

+          echo "Workflow Head Branch: $HEAD_BRANCH"

           echo "Workflow Run ID: ${{ github.event.workflow_run.id }}"

-          echo "Head Commit Message: ${{ github.event.workflow_run.head_commit.message }}"

+          echo "Head Commit Message: $HEAD_COMMIT_MSG"

           echo "GitHub Ref: ${{ github.ref }}"

           echo "GitHub Ref Name: ${{ github.ref_name }}"

           echo "GitHub Event Name: ${{ github.event_name }}"

diff --git a/indra/llmessage/llpacketring.cpp b/indra/llmessage/llpacketring.cpp
index eb6650c6c5..b8284334ea 100644
--- a/indra/llmessage/llpacketring.cpp
+++ b/indra/llmessage/llpacketring.cpp
@@ -209,8 +209,14 @@ S32 LLPacketRing::receiveOrDropBufferedPacket(char *datap, bool drop)
 
     if (!drop)
     {
-        assert(packet_size > 0);
-        memcpy(datap, packet->getData(), packet_size);
+        if (packet_size > 0)
+        {
+            memcpy(datap, packet->getData(), packet_size);
+        }
+        else
+        {
+            assert(false);
+        }
     }
     else
     {
diff --git a/indra/llrender/llglslshader.cpp b/indra/llrender/llglslshader.cpp
index e0c2db058a..aac5e3abc8 100644
--- a/indra/llrender/llglslshader.cpp
+++ b/indra/llrender/llglslshader.cpp
@@ -1114,8 +1114,8 @@ void LLGLSLShader::bind()
 
 void LLGLSLShader::bind(U8 variant)
 {
-    llassert(mGLTFVariants.size() == LLGLSLShader::NUM_GLTF_VARIANTS);
-    llassert(variant < LLGLSLShader::NUM_GLTF_VARIANTS);
+    llassert_always(mGLTFVariants.size() == LLGLSLShader::NUM_GLTF_VARIANTS);
+    llassert_always(variant < LLGLSLShader::NUM_GLTF_VARIANTS);
     mGLTFVariants[variant].bind();
 }
 
@@ -1123,7 +1123,7 @@ void LLGLSLShader::bind(bool rigged)
 {
     if (rigged)
     {
-        llassert(mRiggedVariant);
+        llassert_always(mRiggedVariant);
         mRiggedVariant->bind();
     }
     else
diff --git a/indra/llui/CMakeLists.txt b/indra/llui/CMakeLists.txt
index 5991a5b35e..83b3a220a0 100644
--- a/indra/llui/CMakeLists.txt
+++ b/indra/llui/CMakeLists.txt
@@ -18,6 +18,7 @@ set(llui_SOURCE_FILES
     llbadgeowner.cpp
     llbutton.cpp
     llchatentry.cpp
+    llchatmentionhelper.cpp
     llcheckboxctrl.cpp
     llclipboard.cpp
     llcombobox.cpp
@@ -130,6 +131,7 @@ set(llui_HEADER_FILES
     llcallbackmap.h
     llchatentry.h
     llchat.h
+    llchatmentionhelper.h
     llcheckboxctrl.h
     llclipboard.h
     llcombobox.h
diff --git a/indra/llui/llchatentry.cpp b/indra/llui/llchatentry.cpp
index e8d942b8af..7506cd99c0 100644
--- a/indra/llui/llchatentry.cpp
+++ b/indra/llui/llchatentry.cpp
@@ -52,6 +52,7 @@ LLChatEntry::LLChatEntry(const Params& p)
     mCurrentHistoryLine = mLineHistory.begin();
 
     mAutoIndent = false;
+    mShowChatMentionPicker = true;
     keepSelectionOnReturn(true);
 }
 
diff --git a/indra/llui/llchatmentionhelper.cpp b/indra/llui/llchatmentionhelper.cpp
new file mode 100644
index 0000000000..f7769b2cbe
--- /dev/null
+++ b/indra/llui/llchatmentionhelper.cpp
@@ -0,0 +1,151 @@
+/**
+* @file llchatmentionhelper.cpp
+*
+* $LicenseInfo:firstyear=2025&license=viewerlgpl$
+* Second Life Viewer Source Code
+* Copyright (C) 2025, Linden Research, Inc.
+*
+* This library is free software; you can redistribute it and/or
+* modify it under the terms of the GNU Lesser General Public
+* License as published by the Free Software Foundation;
+* version 2.1 of the License only.
+*
+* This library is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+* Lesser General Public License for more details.
+*
+* You should have received a copy of the GNU Lesser General Public
+* License along with this library; if not, write to the Free Software
+* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*
+* Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+* $/LicenseInfo$
+*/
+
+#include "linden_common.h"
+
+#include "llchatmentionhelper.h"
+#include "llfloater.h"
+#include "llfloaterreg.h"
+#include "lluictrl.h"
+
+constexpr char CHAT_MENTION_HELPER_FLOATER[] = "chat_mention_picker";
+
+bool LLChatMentionHelper::isActive(const LLUICtrl* ctrl) const
+{
+    return mHostHandle.get() == ctrl;
+}
+
+bool LLChatMentionHelper::isCursorInNameMention(const LLWString& wtext, S32 cursor_pos, S32* mention_start_pos) const
+{
+    if (cursor_pos <= 0 || cursor_pos > static_cast<S32>(wtext.size()))
+        return false;
+
+    // Find the beginning of the current word
+    S32 start = cursor_pos - 1;
+    while (start > 0 && wtext[start - 1] != U32(' ') && wtext[start - 1] != U32('\n'))
+    {
+        --start;
+    }
+
+    if (wtext[start] != U32('@'))
+        return false;
+
+    if (mention_start_pos)
+        *mention_start_pos = start;
+
+    S32 word_length = cursor_pos - start;
+
+    if (word_length == 1)
+    {
+        return true;
+    }
+
+    // Get the name after '@'
+    std::string name = wstring_to_utf8str(wtext.substr(start + 1, word_length - 1));
+    LLStringUtil::toLower(name);
+    for (const auto& av_name : mAvatarNames)
+    {
+        if (av_name == name || av_name.find(name) == 0)
+        {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+void LLChatMentionHelper::showHelper(LLUICtrl* host_ctrl, S32 local_x, S32 local_y, const std::string& av_name, std::function<void(std::string)> cb)
+{
+    if (mHelperHandle.isDead())
+    {
+        LLFloater* av_picker_floater = LLFloaterReg::getInstance(CHAT_MENTION_HELPER_FLOATER);
+        mHelperHandle = av_picker_floater->getHandle();
+        mHelperCommitConn = av_picker_floater->setCommitCallback([&](LLUICtrl* ctrl, const LLSD& param) { onCommitName(param.asString()); });
+    }
+    setHostCtrl(host_ctrl);
+    mNameCommitCb = cb;
+
+    S32 floater_x, floater_y;
+    if (!host_ctrl->localPointToOtherView(local_x, local_y, &floater_x, &floater_y, gFloaterView))
+    {
+        LL_WARNS() << "Cannot show helper for non-floater controls." << LL_ENDL;
+        return;
+    }
+
+    LLFloater* av_picker_floater = mHelperHandle.get();
+    LLRect rect = av_picker_floater->getRect();
+    rect.setLeftTopAndSize(floater_x, floater_y + rect.getHeight(), rect.getWidth(), rect.getHeight());
+    av_picker_floater->setRect(rect);
+    av_picker_floater->openFloater(LLSD().with("av_name", av_name));
+}
+
+void LLChatMentionHelper::hideHelper(const LLUICtrl* ctrl)
+{
+    if ((ctrl && !isActive(ctrl)))
+    {
+        return;
+    }
+    setHostCtrl(nullptr);
+}
+
+bool LLChatMentionHelper::handleKey(const LLUICtrl* ctrl, KEY key, MASK mask)
+{
+    if (mHelperHandle.isDead() || !isActive(ctrl))
+    {
+        return false;
+    }
+
+    return mHelperHandle.get()->handleKey(key, mask, true);
+}
+
+void LLChatMentionHelper::onCommitName(std::string name_url)
+{
+    if (!mHostHandle.isDead() && mNameCommitCb)
+    {
+        mNameCommitCb(name_url);
+    }
+}
+
+void LLChatMentionHelper::setHostCtrl(LLUICtrl* host_ctrl)
+{
+    const LLUICtrl* pCurHostCtrl = mHostHandle.get();
+    if (pCurHostCtrl != host_ctrl)
+    {
+        mHostCtrlFocusLostConn.disconnect();
+        mHostHandle.markDead();
+        mNameCommitCb = {};
+
+        if (!mHelperHandle.isDead())
+        {
+            mHelperHandle.get()->closeFloater();
+        }
+
+        if (host_ctrl)
+        {
+            mHostHandle = host_ctrl->getHandle();
+            mHostCtrlFocusLostConn = host_ctrl->setFocusLostCallback(std::bind([&]() { hideHelper(getHostCtrl()); }));
+        }
+    }
+}
diff --git a/indra/llui/llchatmentionhelper.h b/indra/llui/llchatmentionhelper.h
new file mode 100644
index 0000000000..5f95d06f31
--- /dev/null
+++ b/indra/llui/llchatmentionhelper.h
@@ -0,0 +1,66 @@
+/**
+* @file llchatmentionhelper.h
+* @brief Header file for LLChatMentionHelper
+*
+* $LicenseInfo:firstyear=2025&license=viewerlgpl$
+* Second Life Viewer Source Code
+* Copyright (C) 2025, Linden Research, Inc.
+*
+* This library is free software; you can redistribute it and/or
+* modify it under the terms of the GNU Lesser General Public
+* License as published by the Free Software Foundation;
+* version 2.1 of the License only.
+*
+* This library is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+* Lesser General Public License for more details.
+*
+* You should have received a copy of the GNU Lesser General Public
+* License along with this library; if not, write to the Free Software
+* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*
+* Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+* $/LicenseInfo$
+*/
+
+#pragma once
+
+#include "llhandle.h"
+#include "llsingleton.h"
+
+#include <boost/signals2.hpp>
+
+class LLFloater;
+class LLUICtrl;
+
+class LLChatMentionHelper : public LLSingleton<LLChatMentionHelper>
+{
+    LLSINGLETON(LLChatMentionHelper) {}
+    ~LLChatMentionHelper() override {}
+
+public:
+
+    bool isActive(const LLUICtrl* ctrl) const;
+    bool isCursorInNameMention(const LLWString& wtext, S32 cursor_pos, S32* mention_start_pos = nullptr) const;
+    void showHelper(LLUICtrl* host_ctrl, S32 local_x, S32 local_y, const std::string& av_name, std::function<void(std::string)> commit_cb);
+    void hideHelper(const LLUICtrl* ctrl = nullptr);
+
+    bool handleKey(const LLUICtrl* ctrl, KEY key, MASK mask);
+    void onCommitName(std::string name_url);
+
+    void updateAvatarList(std::vector<std::string> av_names) { mAvatarNames = av_names; }
+
+protected:
+    void setHostCtrl(LLUICtrl* host_ctrl);
+    LLUICtrl* getHostCtrl() const { return mHostHandle.get(); }
+
+private:
+    LLHandle<LLUICtrl>  mHostHandle;
+    LLHandle<LLFloater> mHelperHandle;
+    boost::signals2::connection mHostCtrlFocusLostConn;
+    boost::signals2::connection mHelperCommitConn;
+    std::function<void(std::string)> mNameCommitCb;
+
+    std::vector<std::string> mAvatarNames;
+};
diff --git a/indra/llui/llflatlistview.cpp b/indra/llui/llflatlistview.cpp
index b8c833f4fd..8178bada42 100644
--- a/indra/llui/llflatlistview.cpp
+++ b/indra/llui/llflatlistview.cpp
@@ -459,6 +459,7 @@ LLFlatListView::LLFlatListView(const LLFlatListView::Params& p)
   , mNoItemsCommentTextbox(NULL)
   , mIsConsecutiveSelection(false)
   , mKeepSelectionVisibleOnReshape(p.keep_selection_visible_on_reshape)
+  , mFocusOnItemClicked(true)
 {
     mBorderThickness = getBorderWidth();
 
@@ -610,7 +611,10 @@ void LLFlatListView::onItemMouseClick(item_pair_t* item_pair, MASK mask)
         return;
     }
 
-    setFocus(true);
+    if (mFocusOnItemClicked)
+    {
+        setFocus(true);
+    }
 
     bool select_item = !isSelected(item_pair);
 
diff --git a/indra/llui/llflatlistview.h b/indra/llui/llflatlistview.h
index 0ea3115f30..6271231183 100644
--- a/indra/llui/llflatlistview.h
+++ b/indra/llui/llflatlistview.h
@@ -299,6 +299,8 @@ public:
 
     virtual S32 notify(const LLSD& info) override;
 
+    void setFocusOnItemClicked(bool b) { mFocusOnItemClicked = b; }
+
     virtual ~LLFlatListView();
 
 protected:
@@ -423,6 +425,8 @@ private:
 
     bool mKeepSelectionVisibleOnReshape;
 
+    bool mFocusOnItemClicked;
+
     /** All pairs of the list */
     pairs_list_t mItemPairs;
 
diff --git a/indra/llui/llstyle.cpp b/indra/llui/llstyle.cpp
index 4714665e8b..7a0e620d61 100644
--- a/indra/llui/llstyle.cpp
+++ b/indra/llui/llstyle.cpp
@@ -38,11 +38,13 @@ LLStyle::Params::Params()
     color("color", LLColor4::black),
     readonly_color("readonly_color", LLColor4::black),
     selected_color("selected_color", LLColor4::black),
+    highlight_bg_color("highlight_bg_color", LLColor4::green),
     alpha("alpha", 1.f),
     font("font", LLStyle::getDefaultFont()),
     image("image"),
     link_href("href"),
-    is_link("is_link")
+    is_link("is_link"),
+    draw_highlight_bg("draw_highlight_bg", false)
 {}
 
 
@@ -51,12 +53,14 @@ LLStyle::LLStyle(const LLStyle::Params& p)
     mColor(p.color),
     mReadOnlyColor(p.readonly_color),
     mSelectedColor(p.selected_color),
+    mHighlightBgColor(p.highlight_bg_color),
     mFont(p.font()),
     mLink(p.link_href),
     mIsLink(p.is_link.isProvided() ? p.is_link : !p.link_href().empty()),
     mDropShadow(p.drop_shadow),
     mImagep(p.image()),
-    mAlpha(p.alpha)
+    mAlpha(p.alpha),
+    mDrawHighlightBg(p.draw_highlight_bg)
 {}
 
 void LLStyle::setFont(const LLFontGL* font)
diff --git a/indra/llui/llstyle.h b/indra/llui/llstyle.h
index 0c78fe5a9f..71c3f88109 100644
--- a/indra/llui/llstyle.h
+++ b/indra/llui/llstyle.h
@@ -43,15 +43,25 @@ public:
         Optional<LLFontGL::ShadowType>  drop_shadow;
         Optional<LLUIColor>             color,
                                         readonly_color,
-                                        selected_color;
+                                        selected_color,
+                                        highlight_bg_color;
         Optional<F32>                   alpha;
         Optional<const LLFontGL*>       font;
         Optional<LLUIImage*>            image;
         Optional<std::string>           link_href;
         Optional<bool>                  is_link;
+        Optional<bool>                  draw_highlight_bg;
         Params();
     };
     LLStyle(const Params& p = Params());
+
+    enum EUnderlineLink
+    {
+        UNDERLINE_ALWAYS = 0,
+        UNDERLINE_ON_HOVER,
+        UNDERLINE_NEVER
+    };
+
 public:
     const LLUIColor& getColor() const { return mColor; }
     void setColor(const LLUIColor &color) { mColor = color; }
@@ -84,6 +94,9 @@ public:
 
     bool isImage() const { return mImagep.notNull(); }
 
+    bool getDrawHighlightBg() const { return mDrawHighlightBg; }
+    const LLUIColor& getHighlightBgColor() const { return mHighlightBgColor; }
+
     bool operator==(const LLStyle &rhs) const
     {
         return
@@ -91,11 +104,13 @@ public:
             && mColor == rhs.mColor
             && mReadOnlyColor == rhs.mReadOnlyColor
             && mSelectedColor == rhs.mSelectedColor
+            && mHighlightBgColor == rhs.mHighlightBgColor
             && mFont == rhs.mFont
             && mLink == rhs.mLink
             && mImagep == rhs.mImagep
             && mDropShadow == rhs.mDropShadow
-            && mAlpha == rhs.mAlpha;
+            && mAlpha == rhs.mAlpha
+            && mDrawHighlightBg == rhs.mDrawHighlightBg;
     }
 
     bool operator!=(const LLStyle& rhs) const { return !(*this == rhs); }
@@ -112,11 +127,13 @@ private:
     LLUIColor           mColor;
     LLUIColor           mReadOnlyColor;
     LLUIColor           mSelectedColor;
+    LLUIColor           mHighlightBgColor;
     const LLFontGL*     mFont;
     LLPointer<LLUIImage> mImagep;
     F32                 mAlpha;
     bool                mVisible;
     bool                mIsLink;
+    bool                mDrawHighlightBg;
 };
 
 typedef LLPointer<LLStyle> LLStyleSP;
diff --git a/indra/llui/lltextbase.cpp b/indra/llui/lltextbase.cpp
index 41e7094163..c1b01f420b 100644
--- a/indra/llui/lltextbase.cpp
+++ b/indra/llui/lltextbase.cpp
@@ -460,6 +460,62 @@ std::vector<LLRect> LLTextBase::getSelectionRects()
     return selection_rects;
 }
 
+std::vector<std::pair<LLRect, LLUIColor>> LLTextBase::getHighlightedBgRects()
+{
+    std::vector<std::pair<LLRect, LLUIColor>> highlight_rects;
+
+    LLRect content_display_rect = getVisibleDocumentRect();
+
+    // binary search for line that starts before top of visible buffer
+    line_list_t::const_iterator line_iter =
+        std::lower_bound(mLineInfoList.begin(), mLineInfoList.end(), content_display_rect.mTop, compare_bottom());
+    line_list_t::const_iterator end_iter =
+        std::upper_bound(mLineInfoList.begin(), mLineInfoList.end(), content_display_rect.mBottom, compare_top());
+
+    for (; line_iter != end_iter; ++line_iter)
+    {
+            segment_set_t::iterator segment_iter;
+            S32 segment_offset;
+            getSegmentAndOffset(line_iter->mDocIndexStart, &segment_iter, &segment_offset);
+
+            // Use F32 otherwise a string of multiple segments
+            // will accumulate a large error
+            F32 left_precise  = (F32)line_iter->mRect.mLeft;
+            F32 right_precise = (F32)line_iter->mRect.mLeft;
+
+            for (; segment_iter != mSegments.end(); ++segment_iter)
+            {
+                LLTextSegmentPtr segmentp = *segment_iter;
+
+                S32 segment_line_start = segmentp->getStart() + segment_offset;
+                S32 segment_line_end = llmin(segmentp->getEnd(), line_iter->mDocIndexEnd);
+
+                if (segment_line_start > segment_line_end)
+                    break;
+
+                F32 segment_width  = 0;
+                S32 segment_height = 0;
+
+                S32 num_chars = segment_line_end - segment_line_start;
+                segmentp->getDimensionsF32(segment_offset, num_chars, segment_width, segment_height);
+                right_precise += segment_width;
+
+                if (segmentp->getStyle()->getDrawHighlightBg())
+                {
+                    LLRect selection_rect;
+                    selection_rect.mLeft = (S32)left_precise;
+                    selection_rect.mRight = (S32)right_precise;
+                    selection_rect.mBottom = line_iter->mRect.mBottom;
+                    selection_rect.mTop = line_iter->mRect.mTop;
+
+                    highlight_rects.push_back(std::pair(selection_rect, segmentp->getStyle()->getHighlightBgColor()));
+                }
+                left_precise += segment_width;
+            }
+    }
+    return highlight_rects;
+}
+
 // Draws the black box behind the selected text
 void LLTextBase::drawSelectionBackground()
 {
@@ -529,6 +585,71 @@ void LLTextBase::drawSelectionBackground()
     }
 }
 
+void LLTextBase::drawHighlightedBackground()
+{
+    if (!mLineInfoList.empty())
+    {
+        std::vector<std::pair<LLRect, LLUIColor>> highlight_rects = getHighlightedBgRects();
+
+        if (highlight_rects.empty())
+            return;
+
+        gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);
+
+        LLRect content_display_rect = getVisibleDocumentRect();
+
+        for (std::vector<std::pair<LLRect, LLUIColor>>::iterator rect_it = highlight_rects.begin();
+             rect_it != highlight_rects.end(); ++rect_it)
+        {
+            LLRect selection_rect = rect_it->first;
+            const LLColor4& color = rect_it->second;
+            if (mScroller)
+            {
+                // If scroller is On content_display_rect has correct rect and safe to use as is
+                // Note: we might need to account for border
+                selection_rect.translate(mVisibleTextRect.mLeft - content_display_rect.mLeft, mVisibleTextRect.mBottom - content_display_rect.mBottom);
+            }
+            else
+            {
+                // If scroller is Off content_display_rect will have rect from document, adjusted to text width, heigh and position
+                // and we have to acount for offset depending on position
+                S32 v_delta = 0;
+                S32 h_delta = 0;
+                switch (mVAlign)
+                {
+                case LLFontGL::TOP:
+                    v_delta = mVisibleTextRect.mTop - content_display_rect.mTop - mVPad;
+                    break;
+                case LLFontGL::VCENTER:
+                    v_delta = (llmax(mVisibleTextRect.getHeight() - content_display_rect.mTop, -content_display_rect.mBottom) + (mVisibleTextRect.mBottom - content_display_rect.mBottom)) / 2;
+                    break;
+                case LLFontGL::BOTTOM:
+                    v_delta = mVisibleTextRect.mBottom - content_display_rect.mBottom;
+                    break;
+                default:
+                    break;
+                }
+                switch (mHAlign)
+                {
+                case LLFontGL::LEFT:
+                    h_delta = mVisibleTextRect.mLeft - content_display_rect.mLeft + mHPad;
+                    break;
+                case LLFontGL::HCENTER:
+                    h_delta = (llmax(mVisibleTextRect.getWidth() - content_display_rect.mLeft, -content_display_rect.mRight) + (mVisibleTextRect.mRight - content_display_rect.mRight)) / 2;
+                    break;
+                case LLFontGL::RIGHT:
+                    h_delta = mVisibleTextRect.mRight - content_display_rect.mRight;
+                    break;
+                default:
+                    break;
+                }
+                selection_rect.translate(h_delta, v_delta);
+            }
+            gl_rect_2d(selection_rect, color);
+        }
+    }
+}
+
 void LLTextBase::drawCursor()
 {
     F32 alpha = getDrawContext().mAlpha;
@@ -1399,6 +1520,7 @@ void LLTextBase::draw()
             drawChild(mDocumentView);
         }
 
+        drawHighlightedBackground();
         drawSelectionBackground();
         drawText();
         drawCursor();
@@ -2200,20 +2322,20 @@ static LLUIImagePtr image_from_icon_name(const std::string& icon_name)
 }
 
 
-void LLTextBase::appendTextImpl(const std::string &new_text, const LLStyle::Params& input_params)
+void LLTextBase::appendTextImpl(const std::string& new_text, const LLStyle::Params& input_params, bool force_slurl)
 {
     LL_PROFILE_ZONE_SCOPED_CATEGORY_UI;
     LLStyle::Params style_params(getStyleParams());
     style_params.overwriteFrom(input_params);
 
     S32 part = (S32)LLTextParser::WHOLE;
-    if (mParseHTML && !style_params.is_link) // Don't search for URLs inside a link segment (STORM-358).
+    if ((mParseHTML || force_slurl) && !style_params.is_link) // Don't search for URLs inside a link segment (STORM-358).
     {
         S32 start=0,end=0;
         LLUrlMatch match;
         std::string text = new_text;
         while (LLUrlRegistry::instance().findUrl(text, match,
-                boost::bind(&LLTextBase::replaceUrl, this, _1, _2, _3), isContentTrusted() || mAlwaysShowIcons))
+                boost::bind(&LLTextBase::replaceUrl, this, _1, _2, _3), isContentTrusted() || mAlwaysShowIcons, force_slurl))
         {
             start = match.getStart();
             end = match.getEnd()+1;
@@ -2245,7 +2367,7 @@ void LLTextBase::appendTextImpl(const std::string &new_text, const LLStyle::Para
             }
 
             // output the styled Url
-            appendAndHighlightTextImpl(match.getLabel(), part, link_params, match.underlineOnHoverOnly());
+            appendAndHighlightTextImpl(match.getLabel(), part, link_params, match.getUnderline());
             bool tooltip_required =  !match.getTooltip().empty();
 
             // set the tooltip for the Url label
@@ -2260,7 +2382,7 @@ void LLTextBase::appendTextImpl(const std::string &new_text, const LLStyle::Para
             {
                 link_params.color = LLColor4::grey;
                 link_params.readonly_color = LLColor4::grey;
-                appendAndHighlightTextImpl(label, part, link_params, match.underlineOnHoverOnly());
+                appendAndHighlightTextImpl(label, part, link_params, match.getUnderline());
 
                 // set the tooltip for the query part of url
                 if (tooltip_required)
@@ -2428,7 +2550,7 @@ void LLTextBase::appendWidget(const LLInlineViewSegment::Params& params, const s
     insertStringNoUndo(getLength(), widget_wide_text, &segments);
 }
 
-void LLTextBase::appendAndHighlightTextImpl(const std::string &new_text, S32 highlight_part, const LLStyle::Params& style_params, bool underline_on_hover_only)
+void LLTextBase::appendAndHighlightTextImpl(const std::string &new_text, S32 highlight_part, const LLStyle::Params& style_params, e_underline underline_link)
 {
     // Save old state
     S32 selection_start = mSelectionStart;
@@ -2458,7 +2580,7 @@ void LLTextBase::appendAndHighlightTextImpl(const std::string &new_text, S32 hig
             S32 cur_length = getLength();
             LLStyleConstSP sp(new LLStyle(highlight_params));
             LLTextSegmentPtr segmentp;
-            if (underline_on_hover_only || mSkipLinkUnderline)
+            if ((underline_link == e_underline::UNDERLINE_ON_HOVER) || mSkipLinkUnderline)
             {
                 highlight_params.font.style("NORMAL");
                 LLStyleConstSP normal_sp(new LLStyle(highlight_params));
@@ -2482,7 +2604,7 @@ void LLTextBase::appendAndHighlightTextImpl(const std::string &new_text, S32 hig
         S32 segment_start = old_length;
         S32 segment_end = old_length + static_cast<S32>(wide_text.size());
         LLStyleConstSP sp(new LLStyle(style_params));
-        if (underline_on_hover_only || mSkipLinkUnderline)
+        if ((underline_link == e_underline::UNDERLINE_ON_HOVER) || mSkipLinkUnderline)
         {
             LLStyle::Params normal_style_params(style_params);
             normal_style_params.font.style("NORMAL");
@@ -2516,7 +2638,7 @@ void LLTextBase::appendAndHighlightTextImpl(const std::string &new_text, S32 hig
     }
 }
 
-void LLTextBase::appendAndHighlightText(const std::string &new_text, S32 highlight_part, const LLStyle::Params& style_params, bool underline_on_hover_only)
+void LLTextBase::appendAndHighlightText(const std::string &new_text, S32 highlight_part, const LLStyle::Params& style_params, e_underline underline_link)
 {
     if (new_text.empty())
     {
@@ -2531,7 +2653,7 @@ void LLTextBase::appendAndHighlightText(const std::string &new_text, S32 highlig
         if (pos != start)
         {
             std::string str = std::string(new_text,start,pos-start);
-            appendAndHighlightTextImpl(str, highlight_part, style_params, underline_on_hover_only);
+            appendAndHighlightTextImpl(str, highlight_part, style_params, underline_link);
         }
         appendLineBreakSegment(style_params);
         start = pos+1;
@@ -2539,7 +2661,7 @@ void LLTextBase::appendAndHighlightText(const std::string &new_text, S32 highlig
     }
 
     std::string str = std::string(new_text, start, new_text.length() - start);
-    appendAndHighlightTextImpl(str, highlight_part, style_params, underline_on_hover_only);
+    appendAndHighlightTextImpl(str, highlight_part, style_params, underline_link);
 }
 
 
@@ -3336,6 +3458,7 @@ LLNormalTextSegment::LLNormalTextSegment( LLStyleConstSP style, S32 start, S32 e
     mLastGeneration(-1)
 {
     mFontHeight = mStyle->getFont()->getLineHeight();
+    mCanEdit = !mStyle->getDrawHighlightBg();
 
     LLUIImagePtr image = mStyle->getImage();
     if (image.notNull())
diff --git a/indra/llui/lltextbase.h b/indra/llui/lltextbase.h
index e62b56963d..8ca653acb9 100644
--- a/indra/llui/lltextbase.h
+++ b/indra/llui/lltextbase.h
@@ -35,6 +35,7 @@
 #include "llstyle.h"
 #include "llkeywords.h"
 #include "llpanel.h"
+#include "llurlmatch.h"
 
 #include <string>
 #include <vector>
@@ -139,7 +140,7 @@ public:
     /*virtual*/ S32                 getNumChars(S32 num_pixels, S32 segment_offset, S32 line_offset, S32 max_chars, S32 line_ind) const;
     /*virtual*/ void                updateLayout(const class LLTextBase& editor);
     /*virtual*/ F32                 draw(S32 start, S32 end, S32 selection_start, S32 selection_end, const LLRectf& draw_rect);
-    /*virtual*/ bool                canEdit() const { return true; }
+    /*virtual*/ bool                canEdit() const { return mCanEdit; }
     /*virtual*/ const LLUIColor&     getColor() const                    { return mStyle->getColor(); }
     /*virtual*/ LLStyleConstSP      getStyle() const                    { return mStyle; }
     /*virtual*/ void                setStyle(LLStyleConstSP style)  { mStyle = style; }
@@ -161,6 +162,8 @@ protected:
     virtual     const LLWString&    getWText()  const;
     virtual     const S32           getLength() const;
 
+    void setAllowEdit(bool can_edit) { mCanEdit = can_edit; }
+
 protected:
     class LLTextBase&   mEditor;
     LLStyleConstSP      mStyle;
@@ -169,6 +172,8 @@ protected:
     std::string         mTooltip;
     boost::signals2::connection mImageLoadedConnection;
 
+    bool mCanEdit { true };
+
     // font rendering
     LLFontVertexBuffer  mFontBufferPreSelection;
     LLFontVertexBuffer  mFontBufferSelection;
@@ -606,6 +611,7 @@ protected:
         bool operator()(const LLTextSegmentPtr& a, const LLTextSegmentPtr& b) const;
     };
     typedef std::multiset<LLTextSegmentPtr, compare_segment_end> segment_set_t;
+    typedef LLStyle::EUnderlineLink e_underline;
 
     // member functions
     LLTextBase(const Params &p);
@@ -619,12 +625,13 @@ protected:
     virtual void                    drawSelectionBackground(); // draws the black box behind the selected text
     void                            drawCursor();
     void                            drawText();
+    void                            drawHighlightedBackground();
 
     // modify contents
     S32                             insertStringNoUndo(S32 pos, const LLWString &wstr, segment_vec_t* segments = NULL); // returns num of chars actually inserted
     S32                             removeStringNoUndo(S32 pos, S32 length);
     S32                             overwriteCharNoUndo(S32 pos, llwchar wc);
-    void                            appendAndHighlightText(const std::string &new_text, S32 highlight_part, const LLStyle::Params& stylep, bool underline_on_hover_only = false);
+    void                            appendAndHighlightText(const std::string &new_text, S32 highlight_part, const LLStyle::Params& stylep, e_underline underline_link = e_underline::UNDERLINE_ALWAYS);
 
 
     // manage segments
@@ -672,8 +679,9 @@ protected:
     // avatar names are looked up.
     void replaceUrl(const std::string &url, const std::string &label, const std::string& icon);
 
-    void                            appendTextImpl(const std::string &new_text, const LLStyle::Params& input_params = LLStyle::Params());
-    void                            appendAndHighlightTextImpl(const std::string &new_text, S32 highlight_part, const LLStyle::Params& style_params, bool underline_on_hover_only = false);
+    void                            appendTextImpl(const std::string &new_text, const LLStyle::Params& input_params = LLStyle::Params(), bool force_slurl = false);
+    void                            appendAndHighlightTextImpl(const std::string &new_text, S32 highlight_part, const LLStyle::Params& style_params, e_underline underline_link = e_underline::UNDERLINE_ALWAYS);
+    S32 normalizeUri(std::string& uri);
 
 protected:
     // virtual
@@ -683,6 +691,7 @@ protected:
     }
 
     std::vector<LLRect> getSelectionRects();
+    std::vector<std::pair<LLRect, LLUIColor>> getHighlightedBgRects();
 
 protected:
     // text segmentation and flow
diff --git a/indra/llui/lltexteditor.cpp b/indra/llui/lltexteditor.cpp
index fe4cce29ab..cfe729be06 100644
--- a/indra/llui/lltexteditor.cpp
+++ b/indra/llui/lltexteditor.cpp
@@ -60,6 +60,7 @@
 #include "llurlregistry.h"
 #include "lltooltip.h"
 #include "llmenugl.h"
+#include "llchatmentionhelper.h"
 
 #include <queue>
 #include "llcombobox.h"
@@ -270,6 +271,7 @@ LLTextEditor::LLTextEditor(const LLTextEditor::Params& p) :
     mPrevalidator(p.prevalidator()),
     mShowContextMenu(p.show_context_menu),
     mShowEmojiHelper(p.show_emoji_helper),
+    mShowChatMentionPicker(false),
     mEnableTooltipPaste(p.enable_tooltip_paste),
     mPassDelete(false),
     mKeepSelectionOnReturn(false)
@@ -714,6 +716,30 @@ void LLTextEditor::handleEmojiCommit(llwchar emoji)
     }
 }
 
+void LLTextEditor::handleMentionCommit(std::string name_url)
+{
+    S32 mention_start_pos;
+    if (LLChatMentionHelper::instance().isCursorInNameMention(getWText(), mCursorPos, &mention_start_pos))
+    {
+        remove(mention_start_pos, mCursorPos - mention_start_pos, true);
+        insert(mention_start_pos, utf8str_to_wstring(name_url), false, LLTextSegmentPtr());
+
+        std::string new_text(wstring_to_utf8str(getConvertedText()));
+        clear();
+        appendTextImpl(new_text, LLStyle::Params(), true);
+
+        segment_set_t::const_iterator it = getSegIterContaining(mention_start_pos);
+        if (it != mSegments.end())
+        {
+            setCursorPos((*it)->getEnd() + 1);
+        }
+        else
+        {
+            setCursorPos(mention_start_pos);
+        }
+    }
+}
+
 bool LLTextEditor::handleMouseDown(S32 x, S32 y, MASK mask)
 {
     bool    handled = false;
@@ -1103,6 +1129,7 @@ void LLTextEditor::removeCharOrTab()
         }
 
         tryToShowEmojiHelper();
+        tryToShowMentionHelper();
     }
     else
     {
@@ -1128,6 +1155,7 @@ void LLTextEditor::removeChar()
         setCursorPos(mCursorPos - 1);
         removeChar(mCursorPos);
         tryToShowEmojiHelper();
+        tryToShowMentionHelper();
     }
     else
     {
@@ -1189,6 +1217,7 @@ void LLTextEditor::addChar(llwchar wc)
 
     setCursorPos(mCursorPos + addChar( mCursorPos, wc ));
     tryToShowEmojiHelper();
+    tryToShowMentionHelper();
 
     if (!mReadOnly && mAutoreplaceCallback != NULL)
     {
@@ -1247,6 +1276,31 @@ void LLTextEditor::tryToShowEmojiHelper()
     }
 }
 
+void LLTextEditor::tryToShowMentionHelper()
+{
+    if (mReadOnly || !mShowChatMentionPicker)
+        return;
+
+    S32 mention_start_pos;
+    LLWString text(getWText());
+    if (LLChatMentionHelper::instance().isCursorInNameMention(text, mCursorPos, &mention_start_pos))
+    {
+        const LLRect cursor_rect(getLocalRectFromDocIndex(mention_start_pos));
+        std::string name_part(wstring_to_utf8str(text.substr(mention_start_pos, mCursorPos - mention_start_pos)));
+        name_part.erase(0, 1);
+        auto cb = [this](std::string name_url)
+        {
+            handleMentionCommit(name_url);
+        };
+        LLChatMentionHelper::instance().showHelper(this, cursor_rect.mLeft, cursor_rect.mTop, name_part, cb);
+    }
+    else
+    {
+        LLChatMentionHelper::instance().hideHelper();
+    }
+}
+
+
 void LLTextEditor::addLineBreakChar(bool group_together)
 {
     if( !getEnabled() )
@@ -1873,7 +1927,7 @@ bool LLTextEditor::handleKeyHere(KEY key, MASK mask )
     // not handled and let the parent take care of field movement.
     if (KEY_TAB == key && mTabsToNextField)
     {
-        return false;
+        return mShowChatMentionPicker && LLChatMentionHelper::instance().handleKey(this, key, mask);
     }
 
     if (mReadOnly && mScroller)
@@ -1884,9 +1938,13 @@ bool LLTextEditor::handleKeyHere(KEY key, MASK mask )
     }
     else
     {
-        if (!mReadOnly && mShowEmojiHelper && LLEmojiHelper::instance().handleKey(this, key, mask))
+        if (!mReadOnly)
         {
-            return true;
+            if ((mShowEmojiHelper && LLEmojiHelper::instance().handleKey(this, key, mask)) ||
+                (mShowChatMentionPicker && LLChatMentionHelper::instance().handleKey(this, key, mask)))
+            {
+                return true;
+            }
         }
 
         if (mEnableTooltipPaste &&
@@ -3083,3 +3141,21 @@ S32 LLTextEditor::spacesPerTab()
 {
     return SPACES_PER_TAB;
 }
+
+LLWString LLTextEditor::getConvertedText() const
+{
+    LLWString text = getWText();
+    S32 diff = 0;
+    for (auto segment : mSegments)
+    {
+        if (segment && segment->getStyle() && segment->getStyle()->getDrawHighlightBg())
+        {
+            S32 seg_length = segment->getEnd() - segment->getStart();
+            std::string slurl = segment->getStyle()->getLinkHREF();
+
+            text.replace(segment->getStart() + diff, seg_length, utf8str_to_wstring(slurl));
+            diff += (S32)slurl.size() - seg_length;
+        }
+    }
+    return text;
+}
diff --git a/indra/llui/lltexteditor.h b/indra/llui/lltexteditor.h
index 353a7b93a0..882bb145df 100644
--- a/indra/llui/lltexteditor.h
+++ b/indra/llui/lltexteditor.h
@@ -95,6 +95,8 @@ public:
     void    insertEmoji(llwchar emoji);
     void    handleEmojiCommit(llwchar emoji);
 
+    void handleMentionCommit(std::string name_url);
+
     // mousehandler overrides
     virtual bool    handleMouseDown(S32 x, S32 y, MASK mask);
     virtual bool    handleMouseUp(S32 x, S32 y, MASK mask);
@@ -212,6 +214,8 @@ public:
 
     void            setPassDelete(bool b) { mPassDelete = b; }
 
+    LLWString       getConvertedText() const;
+
 protected:
     void            showContextMenu(S32 x, S32 y);
     void            drawPreeditMarker();
@@ -254,6 +258,7 @@ protected:
     S32             remove(S32 pos, S32 length, bool group_with_next_op);
 
     void            tryToShowEmojiHelper();
+    void            tryToShowMentionHelper();
     void            focusLostHelper();
     void            updateAllowingLanguageInput();
     bool            hasPreeditString() const;
@@ -291,6 +296,7 @@ protected:
 
     bool                mAutoIndent;
     bool                mParseOnTheFly;
+    bool                mShowChatMentionPicker;
 
     void                updateLinkSegments();
     void                keepSelectionOnReturn(bool keep) { mKeepSelectionOnReturn = keep; }
diff --git a/indra/llui/llurlentry.cpp b/indra/llui/llurlentry.cpp
index 77f132e9d8..34138da34d 100644
--- a/indra/llui/llurlentry.cpp
+++ b/indra/llui/llurlentry.cpp
@@ -29,7 +29,6 @@
 #include "llurlentry.h"
 #include "lluictrl.h"
 #include "lluri.h"
-#include "llurlmatch.h"
 #include "llurlregistry.h"
 #include "lluriparser.h"
 
@@ -48,7 +47,7 @@
 // Utility functions
 std::string localize_slapp_label(const std::string& url, const std::string& full_name);
 
-
+LLUUID LLUrlEntryBase::sAgentID(LLUUID::null);
 LLUrlEntryBase::LLUrlEntryBase()
 {
 }
@@ -68,7 +67,7 @@ std::string LLUrlEntryBase::getIcon(const std::string &url)
     return mIcon;
 }
 
-LLStyle::Params LLUrlEntryBase::getStyle() const
+LLStyle::Params LLUrlEntryBase::getStyle(const std::string &url) const
 {
     LLStyle::Params style_params;
     style_params.color = LLUIColorTable::instance().getColor("HTMLLinkColor");
@@ -667,10 +666,14 @@ std::string LLUrlEntryAgent::getTooltip(const std::string &string) const
     return LLTrans::getString("TooltipAgentUrl");
 }
 
-bool LLUrlEntryAgent::underlineOnHoverOnly(const std::string &string) const
+LLStyle::EUnderlineLink LLUrlEntryAgent::getUnderline(const std::string& string) const
 {
     std::string url = getUrl(string);
-    return LLStringUtil::endsWith(url, "/about") || LLStringUtil::endsWith(url, "/inspect");
+    if (LLStringUtil::endsWith(url, "/about") || LLStringUtil::endsWith(url, "/inspect"))
+    {
+        return LLStyle::EUnderlineLink::UNDERLINE_ON_HOVER;
+    }
+    return LLStyle::EUnderlineLink::UNDERLINE_ALWAYS;
 }
 
 std::string LLUrlEntryAgent::getLabel(const std::string &url, const LLUrlLabelCallback &cb)
@@ -712,11 +715,12 @@ std::string LLUrlEntryAgent::getLabel(const std::string &url, const LLUrlLabelCa
     }
 }
 
-LLStyle::Params LLUrlEntryAgent::getStyle() const
+LLStyle::Params LLUrlEntryAgent::getStyle(const std::string &url) const
 {
-    LLStyle::Params style_params = LLUrlEntryBase::getStyle();
+    LLStyle::Params style_params = LLUrlEntryBase::getStyle(url);
     style_params.color = LLUIColorTable::instance().getColor("HTMLLinkColor");
     style_params.readonly_color = LLUIColorTable::instance().getColor("HTMLLinkColor");
+
     return style_params;
 }
 
@@ -751,6 +755,10 @@ std::string localize_slapp_label(const std::string& url, const std::string& full
     {
         return LLTrans::getString("SLappAgentRemoveFriend") + " " + full_name;
     }
+    if (LLStringUtil::endsWith(url, "/mention"))
+    {
+        return "@" + full_name;
+    }
     return full_name;
 }
 
@@ -762,6 +770,34 @@ std::string LLUrlEntryAgent::getIcon(const std::string &url)
     return mIcon;
 }
 
+///
+/// LLUrlEntryAgentMention Describes a chat mention Url, e.g.,
+/// secondlife:///app/agent/0e346d8b-4433-4d66-a6b0-fd37083abc4c/mention
+///
+LLUrlEntryAgentMention::LLUrlEntryAgentMention()
+{
+    mPattern  = boost::regex(APP_HEADER_REGEX "/agent/[\\da-f-]+/mention", boost::regex::perl | boost::regex::icase);
+    mMenuName = "menu_url_agent.xml";
+    mIcon = std::string();
+}
+
+LLStyle::EUnderlineLink LLUrlEntryAgentMention::getUnderline(const std::string& string) const
+{
+    return LLStyle::EUnderlineLink::UNDERLINE_NEVER;
+}
+
+LLStyle::Params LLUrlEntryAgentMention::getStyle(const std::string& url) const
+{
+    LLStyle::Params style_params = LLUrlEntryAgent::getStyle(url);
+    style_params.font.style = "NORMAL";
+    style_params.draw_highlight_bg = true;
+
+    LLUUID agent_id(getIDStringFromUrl(url));
+    style_params.highlight_bg_color = LLUIColorTable::instance().getColor((agent_id == sAgentID) ? "ChatSelfMentionHighlight" : "ChatMentionHighlight");
+
+    return style_params;
+}
+
 //
 // LLUrlEntryAgentName describes a Second Life agent name Url, e.g.,
 // secondlife:///app/agent/0e346d8b-4433-4d66-a6b0-fd37083abc4c/(completename|displayname|username)
@@ -823,7 +859,7 @@ std::string LLUrlEntryAgentName::getLabel(const std::string &url, const LLUrlLab
     }
 }
 
-LLStyle::Params LLUrlEntryAgentName::getStyle() const
+LLStyle::Params LLUrlEntryAgentName::getStyle(const std::string &url) const
 {
     // don't override default colors
     return LLStyle::Params().is_link(false);
@@ -959,9 +995,9 @@ std::string LLUrlEntryGroup::getLabel(const std::string &url, const LLUrlLabelCa
     }
 }
 
-LLStyle::Params LLUrlEntryGroup::getStyle() const
+LLStyle::Params LLUrlEntryGroup::getStyle(const std::string &url) const
 {
-    LLStyle::Params style_params = LLUrlEntryBase::getStyle();
+    LLStyle::Params style_params = LLUrlEntryBase::getStyle(url);
     style_params.color = LLUIColorTable::instance().getColor("HTMLLinkColor");
     style_params.readonly_color = LLUIColorTable::instance().getColor("HTMLLinkColor");
     return style_params;
@@ -1037,7 +1073,6 @@ std::string LLUrlEntryChat::getLabel(const std::string &url, const LLUrlLabelCal
 }
 
 // LLUrlEntryParcel statics.
-LLUUID  LLUrlEntryParcel::sAgentID(LLUUID::null);
 LLUUID  LLUrlEntryParcel::sSessionID(LLUUID::null);
 LLHost  LLUrlEntryParcel::sRegionHost;
 bool    LLUrlEntryParcel::sDisconnected(false);
@@ -1371,17 +1406,17 @@ std::string LLUrlEntrySLLabel::getTooltip(const std::string &string) const
     return LLUrlEntryBase::getTooltip(string);
 }
 
-bool LLUrlEntrySLLabel::underlineOnHoverOnly(const std::string &string) const
+LLStyle::EUnderlineLink LLUrlEntrySLLabel::getUnderline(const std::string& string) const
 {
     std::string url = getUrl(string);
-    LLUrlMatch match;
+    LLUrlMatch  match;
     if (LLUrlRegistry::instance().findUrl(url, match))
     {
-        return match.underlineOnHoverOnly();
+        return match.getUnderline();
     }
 
     // unrecognized URL? should not happen
-    return LLUrlEntryBase::underlineOnHoverOnly(string);
+    return LLUrlEntryBase::getUnderline(string);
 }
 
 //
@@ -1445,7 +1480,7 @@ std::string LLUrlEntryNoLink::getLabel(const std::string &url, const LLUrlLabelC
     return getUrl(url);
 }
 
-LLStyle::Params LLUrlEntryNoLink::getStyle() const
+LLStyle::Params LLUrlEntryNoLink::getStyle(const std::string &url) const
 {
     // Don't render as URL (i.e. no context menu or hand cursor).
     return LLStyle::Params().is_link(false);
diff --git a/indra/llui/llurlentry.h b/indra/llui/llurlentry.h
index fffee88496..740e99acfd 100644
--- a/indra/llui/llurlentry.h
+++ b/indra/llui/llurlentry.h
@@ -85,7 +85,7 @@ public:
     virtual std::string getIcon(const std::string &url);
 
     /// Return the style to render the displayed text
-    virtual LLStyle::Params getStyle() const;
+    virtual LLStyle::Params getStyle(const std::string &url) const;
 
     /// Given a matched Url, return a tooltip string for the hyperlink
     virtual std::string getTooltip(const std::string &string) const { return mTooltip; }
@@ -96,11 +96,12 @@ public:
     /// Return the name of a SL location described by this Url, if any
     virtual std::string getLocation(const std::string &url) const { return ""; }
 
-    /// Should this link text be underlined only when mouse is hovered over it?
-    virtual bool underlineOnHoverOnly(const std::string &string) const { return false; }
+    virtual LLStyle::EUnderlineLink getUnderline(const std::string& string) const { return LLStyle::EUnderlineLink::UNDERLINE_ALWAYS; }
 
     virtual bool isTrusted() const { return false; }
 
+    virtual bool getSkipProfileIcon(const std::string& string) const { return false; }
+
     virtual LLUUID  getID(const std::string &string) const { return LLUUID::null; }
 
     bool isLinkDisabled() const;
@@ -109,6 +110,8 @@ public:
 
     virtual bool isSLURLvalid(const std::string &url) const { return true; };
 
+    static void setAgentID(const LLUUID& id) { sAgentID = id; }
+
 protected:
     std::string getIDStringFromUrl(const std::string &url) const;
     std::string escapeUrl(const std::string &url) const;
@@ -130,6 +133,8 @@ protected:
     std::string                                     mMenuName;
     std::string                                     mTooltip;
     std::multimap<std::string, LLUrlEntryObserver>  mObservers;
+
+    static LLUUID sAgentID;
 };
 
 ///
@@ -224,9 +229,11 @@ public:
     /*virtual*/ std::string getLabel(const std::string &url, const LLUrlLabelCallback &cb);
     /*virtual*/ std::string getIcon(const std::string &url);
     /*virtual*/ std::string getTooltip(const std::string &string) const;
-    /*virtual*/ LLStyle::Params getStyle() const;
+    /*virtual*/ LLStyle::Params getStyle(const std::string &url) const;
     /*virtual*/ LLUUID  getID(const std::string &string) const;
-    /*virtual*/ bool underlineOnHoverOnly(const std::string &string) const;
+
+    LLStyle::EUnderlineLink getUnderline(const std::string& string) const;
+
 protected:
     /*virtual*/ void callObservers(const std::string &id, const std::string &label, const std::string& icon);
 private:
@@ -237,6 +244,19 @@ private:
 };
 
 ///
+/// LLUrlEntryAgentMention Describes a chat mention Url, e.g.,
+/// secondlife:///app/agent/0e346d8b-4433-4d66-a6b0-fd37083abc4c/mention
+class LLUrlEntryAgentMention : public LLUrlEntryAgent
+{
+public:
+    LLUrlEntryAgentMention();
+
+    LLStyle::Params getStyle(const std::string& url) const;
+    LLStyle::EUnderlineLink getUnderline(const std::string& string) const;
+    bool getSkipProfileIcon(const std::string& string) const { return true; };
+};
+
+///
 /// LLUrlEntryAgentName Describes a Second Life agent name Url, e.g.,
 /// secondlife:///app/agent/0e346d8b-4433-4d66-a6b0-fd37083abc4c/(completename|displayname|username)
 /// that displays various forms of user name
@@ -257,7 +277,7 @@ public:
         mAvatarNameCacheConnections.clear();
     }
     /*virtual*/ std::string getLabel(const std::string &url, const LLUrlLabelCallback &cb);
-    /*virtual*/ LLStyle::Params getStyle() const;
+    /*virtual*/ LLStyle::Params getStyle(const std::string &url) const;
 protected:
     // override this to pull out relevant name fields
     virtual std::string getName(const LLAvatarName& avatar_name) = 0;
@@ -339,7 +359,7 @@ class LLUrlEntryGroup : public LLUrlEntryBase
 public:
     LLUrlEntryGroup();
     /*virtual*/ std::string getLabel(const std::string &url, const LLUrlLabelCallback &cb);
-    /*virtual*/ LLStyle::Params getStyle() const;
+    /*virtual*/ LLStyle::Params getStyle(const std::string &url) const;
     /*virtual*/ LLUUID  getID(const std::string &string) const;
 private:
     void onGroupNameReceived(const LLUUID& id, const std::string& name, bool is_group);
@@ -411,17 +431,15 @@ public:
     // Processes parcel label and triggers notifying observers.
     static void processParcelInfo(const LLParcelData& parcel_data);
 
-    // Next 4 setters are used to update agent and viewer connection information
+    // Next setters are used to update agent and viewer connection information
     // upon events like user login, viewer disconnect and user changing region host.
     // These setters are made public to be accessible from newview and should not be
     // used in other cases.
-    static void setAgentID(const LLUUID& id) { sAgentID = id; }
     static void setSessionID(const LLUUID& id) { sSessionID = id; }
     static void setRegionHost(const LLHost& host) { sRegionHost = host; }
     static void setDisconnected(bool disconnected) { sDisconnected = disconnected; }
 
 private:
-    static LLUUID                       sAgentID;
     static LLUUID                       sSessionID;
     static LLHost                       sRegionHost;
     static bool                         sDisconnected;
@@ -486,7 +504,7 @@ public:
     /*virtual*/ std::string getLabel(const std::string &url, const LLUrlLabelCallback &cb);
     /*virtual*/ std::string getUrl(const std::string &string) const;
     /*virtual*/ std::string getTooltip(const std::string &string) const;
-    /*virtual*/ bool underlineOnHoverOnly(const std::string &string) const;
+    LLStyle::EUnderlineLink getUnderline(const std::string& string) const;
 };
 
 ///
@@ -510,7 +528,7 @@ public:
     LLUrlEntryNoLink();
     /*virtual*/ std::string getLabel(const std::string &url, const LLUrlLabelCallback &cb);
     /*virtual*/ std::string getUrl(const std::string &string) const;
-    /*virtual*/ LLStyle::Params getStyle() const;
+    /*virtual*/ LLStyle::Params getStyle(const std::string &url) const;
 };
 
 ///
diff --git a/indra/llui/llurlmatch.cpp b/indra/llui/llurlmatch.cpp
index bfa3b167b1..f093934ca9 100644
--- a/indra/llui/llurlmatch.cpp
+++ b/indra/llui/llurlmatch.cpp
@@ -37,8 +37,9 @@ LLUrlMatch::LLUrlMatch() :
     mIcon(""),
     mMenuName(""),
     mLocation(""),
-    mUnderlineOnHoverOnly(false),
-    mTrusted(false)
+    mUnderline(e_underline::UNDERLINE_ALWAYS),
+    mTrusted(false),
+    mSkipProfileIcon(false)
 {
 }
 
@@ -46,7 +47,7 @@ void LLUrlMatch::setValues(U32 start, U32 end, const std::string &url, const std
                            const std::string& query, const std::string &tooltip,
                            const std::string &icon, const LLStyle::Params& style,
                            const std::string &menu, const std::string &location,
-                           const LLUUID& id, bool underline_on_hover_only, bool trusted)
+                           const LLUUID& id, e_underline underline, bool trusted, bool skip_icon)
 {
     mStart = start;
     mEnd = end;
@@ -60,6 +61,7 @@ void LLUrlMatch::setValues(U32 start, U32 end, const std::string &url, const std
     mMenuName = menu;
     mLocation = location;
     mID = id;
-    mUnderlineOnHoverOnly = underline_on_hover_only;
+    mUnderline = underline;
     mTrusted = trusted;
+    mSkipProfileIcon = skip_icon;
 }
diff --git a/indra/llui/llurlmatch.h b/indra/llui/llurlmatch.h
index 887796bb37..418a21f963 100644
--- a/indra/llui/llurlmatch.h
+++ b/indra/llui/llurlmatch.h
@@ -79,18 +79,20 @@ public:
     /// return the SL location that this Url describes, or "" if none.
     std::string getLocation() const { return mLocation; }
 
-    /// Should this link text be underlined only when mouse is hovered over it?
-    bool underlineOnHoverOnly() const { return mUnderlineOnHoverOnly; }
+    typedef LLStyle::EUnderlineLink e_underline;
+    e_underline getUnderline() const { return mUnderline; }
 
     /// Return true if Url is trusted.
     bool isTrusted() const { return mTrusted; }
 
+    bool getSkipProfileIcon() const { return mSkipProfileIcon; }
+
     /// Change the contents of this match object (used by LLUrlRegistry)
     void setValues(U32 start, U32 end, const std::string &url, const std::string &label,
                    const std::string& query, const std::string &tooltip, const std::string &icon,
                    const LLStyle::Params& style, const std::string &menu,
                    const std::string &location, const LLUUID& id,
-                   bool underline_on_hover_only = false, bool trusted = false);
+                   e_underline underline = e_underline::UNDERLINE_ALWAYS, bool trusted = false, bool skip_icon = false);
 
     const LLUUID& getID() const { return mID; }
 private:
@@ -105,8 +107,9 @@ private:
     std::string mLocation;
     LLUUID      mID;
     LLStyle::Params mStyle;
-    bool        mUnderlineOnHoverOnly;
+    e_underline mUnderline;
     bool        mTrusted;
+    bool mSkipProfileIcon;
 };
 
 #endif
diff --git a/indra/llui/llurlregistry.cpp b/indra/llui/llurlregistry.cpp
index cec1ddfc57..02d88c83fb 100644
--- a/indra/llui/llurlregistry.cpp
+++ b/indra/llui/llurlregistry.cpp
@@ -62,6 +62,8 @@ LLUrlRegistry::LLUrlRegistry()
     registerUrl(new LLUrlEntryAgentUserName());
     // LLUrlEntryAgent*Name must appear before LLUrlEntryAgent since
     // LLUrlEntryAgent is a less specific (catchall for agent urls)
+    mUrlEntryAgentMention = new LLUrlEntryAgentMention();
+    registerUrl(mUrlEntryAgentMention);
     registerUrl(new LLUrlEntryAgent());
     registerUrl(new LLUrlEntryChat());
     registerUrl(new LLUrlEntryGroup());
@@ -155,7 +157,7 @@ static bool stringHasUrl(const std::string &text)
             text.find("@") != std::string::npos);
 }
 
-bool LLUrlRegistry::findUrl(const std::string &text, LLUrlMatch &match, const LLUrlLabelCallback &cb, bool is_content_trusted)
+bool LLUrlRegistry::findUrl(const std::string &text, LLUrlMatch &match, const LLUrlLabelCallback &cb, bool is_content_trusted, bool skip_non_mentions)
 {
     // avoid costly regexes if there is clearly no URL in the text
     if (! stringHasUrl(text))
@@ -176,6 +178,11 @@ bool LLUrlRegistry::findUrl(const std::string &text, LLUrlMatch &match, const LL
             continue;
         }
 
+        if (skip_non_mentions && (mUrlEntryAgentMention != *it))
+        {
+            continue;
+        }
+
         LLUrlEntryBase *url_entry = *it;
 
         U32 start = 0, end = 0;
@@ -233,12 +240,13 @@ bool LLUrlRegistry::findUrl(const std::string &text, LLUrlMatch &match, const LL
                         match_entry->getQuery(url),
                         match_entry->getTooltip(url),
                         match_entry->getIcon(url),
-                        match_entry->getStyle(),
+                        match_entry->getStyle(url),
                         match_entry->getMenuName(),
                         match_entry->getLocation(url),
                         match_entry->getID(url),
-                        match_entry->underlineOnHoverOnly(url),
-                        match_entry->isTrusted());
+                        match_entry->getUnderline(url),
+                        match_entry->isTrusted(),
+                        match_entry->getSkipProfileIcon(url));
         return true;
     }
 
@@ -274,7 +282,9 @@ bool LLUrlRegistry::findUrl(const LLWString &text, LLUrlMatch &match, const LLUr
                         match.getMenuName(),
                         match.getLocation(),
                         match.getID(),
-                        match.underlineOnHoverOnly());
+                        match.getUnderline(),
+                        false,
+                        match.getSkipProfileIcon());
         return true;
     }
     return false;
diff --git a/indra/llui/llurlregistry.h b/indra/llui/llurlregistry.h
index c22af0dbc4..b9502f4592 100644
--- a/indra/llui/llurlregistry.h
+++ b/indra/llui/llurlregistry.h
@@ -75,7 +75,7 @@ public:
     /// your callback is invoked if the matched Url's label changes in the future
     bool findUrl(const std::string &text, LLUrlMatch &match,
                  const LLUrlLabelCallback &cb = &LLUrlRegistryNullCallback,
-                 bool is_content_trusted = false);
+                 bool is_content_trusted = false, bool skip_non_mentions = false);
 
     /// a slightly less efficient version of findUrl for wide strings
     bool findUrl(const LLWString &text, LLUrlMatch &match,
@@ -101,6 +101,7 @@ private:
     LLUrlEntryBase* mUrlEntrySLLabel;
     LLUrlEntryBase* mUrlEntryNoLink;
     LLUrlEntryBase* mUrlEntryKeybinding;
+    LLUrlEntryBase* mUrlEntryAgentMention;
 };
 
 #endif
diff --git a/indra/newview/CMakeLists.txt b/indra/newview/CMakeLists.txt
index 77d9171f3f..473ca60728 100644
--- a/indra/newview/CMakeLists.txt
+++ b/indra/newview/CMakeLists.txt
@@ -212,6 +212,7 @@ set(viewer_SOURCE_FILES
     llfloatercamera.cpp
     llfloatercamerapresets.cpp
     llfloaterchangeitemthumbnail.cpp
+    llfloaterchatmentionpicker.cpp
     llfloaterchatvoicevolume.cpp
     llfloaterclassified.cpp
     llfloatercolorpicker.cpp
@@ -887,6 +888,7 @@ set(viewer_HEADER_FILES
     llfloaterbuyland.h
     llfloatercamerapresets.h
     llfloaterchangeitemthumbnail.h
+    llfloaterchatmentionpicker.h
     llfloatercamera.h
     llfloaterchatvoicevolume.h
     llfloaterclassified.h
diff --git a/indra/newview/VIEWER_VERSION.txt b/indra/newview/VIEWER_VERSION.txt
index 991d8e5c5f..099f298456 100644
--- a/indra/newview/VIEWER_VERSION.txt
+++ b/indra/newview/VIEWER_VERSION.txt
@@ -1 +1 @@
-7.1.13
+7.1.14
diff --git a/indra/newview/gltfscenemanager.cpp b/indra/newview/gltfscenemanager.cpp
index bf3fada3bd..9a381f9ba6 100644
--- a/indra/newview/gltfscenemanager.cpp
+++ b/indra/newview/gltfscenemanager.cpp
@@ -643,6 +643,12 @@ void GLTFSceneManager::render(Asset& asset, U8 variant)
         return;
     }
 
+    if (gGLTFPBRMetallicRoughnessProgram.mGLTFVariants.size() <= variant)
+    {
+        llassert(false); // mGLTFVariants should have been initialized
+        return;
+    }
+
     for (U32 ds = 0; ds < 2; ++ds)
     {
         RenderData& rd = asset.mRenderData[ds];
diff --git a/indra/newview/llappviewer.cpp b/indra/newview/llappviewer.cpp
index 87b165b739..3cc84666ec 100644
--- a/indra/newview/llappviewer.cpp
+++ b/indra/newview/llappviewer.cpp
@@ -485,7 +485,7 @@ static void deferred_ui_audio_callback(const LLUUID& uuid)
 
 bool    create_text_segment_icon_from_url_match(LLUrlMatch* match,LLTextBase* base)
 {
-    if(!match || !base || base->getPlainText())
+    if (!match || match->getSkipProfileIcon() || !base || base->getPlainText())
         return false;
 
     LLUUID match_id = match->getID();
diff --git a/indra/newview/llavatarlist.cpp b/indra/newview/llavatarlist.cpp
index 52cd86951d..5f9d03ca66 100644
--- a/indra/newview/llavatarlist.cpp
+++ b/indra/newview/llavatarlist.cpp
@@ -147,6 +147,7 @@ LLAvatarList::LLAvatarList(const Params& p)
 , mShowSpeakingIndicator(p.show_speaking_indicator)
 , mShowPermissions(p.show_permissions_granted)
 , mShowCompleteName(false)
+, mForceCompleteName(false)
 {
     setCommitOnSelectionChange(true);
 
@@ -183,7 +184,7 @@ void LLAvatarList::setShowIcons(std::string param_name)
 
 std::string LLAvatarList::getAvatarName(LLAvatarName av_name)
 {
-    return mShowCompleteName? av_name.getCompleteName(false) : av_name.getDisplayName();
+    return mShowCompleteName? av_name.getCompleteName(false, mForceCompleteName) : av_name.getDisplayName();
 }
 
 // virtual
@@ -381,7 +382,7 @@ void LLAvatarList::updateAvatarNames()
     for( std::vector<LLPanel*>::const_iterator it = items.begin(); it != items.end(); it++)
     {
         LLAvatarListItem* item = static_cast<LLAvatarListItem*>(*it);
-        item->setShowCompleteName(mShowCompleteName);
+        item->setShowCompleteName(mShowCompleteName, mForceCompleteName);
         item->updateAvatarName();
     }
     mNeedUpdateNames = false;
@@ -421,6 +422,11 @@ boost::signals2::connection LLAvatarList::setItemDoubleClickCallback(const mouse
     return mItemDoubleClickSignal.connect(cb);
 }
 
+boost::signals2::connection LLAvatarList::setItemClickedCallback(const mouse_signal_t::slot_type& cb)
+{
+    return mItemClickedSignal.connect(cb);
+}
+
 //virtual
 S32 LLAvatarList::notifyParent(const LLSD& info)
 {
@@ -435,7 +441,7 @@ S32 LLAvatarList::notifyParent(const LLSD& info)
 void LLAvatarList::addNewItem(const LLUUID& id, const std::string& name, bool is_online, EAddPosition pos)
 {
     LLAvatarListItem* item = new LLAvatarListItem();
-    item->setShowCompleteName(mShowCompleteName);
+    item->setShowCompleteName(mShowCompleteName, mForceCompleteName);
     // This sets the name as a side effect
     item->setAvatarId(id, mSessionID, mIgnoreOnlineStatus);
     item->setOnline(mIgnoreOnlineStatus ? true : is_online);
@@ -451,6 +457,7 @@ void LLAvatarList::addNewItem(const LLUUID& id, const std::string& name, bool is
 
 
     item->setDoubleClickCallback(boost::bind(&LLAvatarList::onItemDoubleClicked, this, _1, _2, _3, _4));
+    item->setMouseDownCallback(boost::bind(&LLAvatarList::onItemClicked, this, _1, _2, _3, _4));
 
     addItem(item, id, pos);
 }
@@ -609,6 +616,11 @@ void LLAvatarList::onItemDoubleClicked(LLUICtrl* ctrl, S32 x, S32 y, MASK mask)
     mItemDoubleClickSignal(ctrl, x, y, mask);
 }
 
+void LLAvatarList::onItemClicked(LLUICtrl* ctrl, S32 x, S32 y, MASK mask)
+{
+    mItemClickedSignal(ctrl, x, y, mask);
+}
+
 bool LLAvatarItemComparator::compare(const LLPanel* item1, const LLPanel* item2) const
 {
     const LLAvatarListItem* avatar_item1 = dynamic_cast<const LLAvatarListItem*>(item1);
diff --git a/indra/newview/llavatarlist.h b/indra/newview/llavatarlist.h
index 37ad578a20..97b4f05985 100644
--- a/indra/newview/llavatarlist.h
+++ b/indra/newview/llavatarlist.h
@@ -98,11 +98,13 @@ public:
 
     boost::signals2::connection setItemDoubleClickCallback(const mouse_signal_t::slot_type& cb);
 
+    boost::signals2::connection setItemClickedCallback(const mouse_signal_t::slot_type& cb);
+
     virtual S32 notifyParent(const LLSD& info);
 
     void handleDisplayNamesOptionChanged();
 
-    void setShowCompleteName(bool show) { mShowCompleteName = show;};
+    void setShowCompleteName(bool show, bool force = false) { mShowCompleteName = show; mForceCompleteName = force; };
 
 protected:
     void refresh();
@@ -117,6 +119,7 @@ protected:
     void updateLastInteractionTimes();
     void rebuildNames();
     void onItemDoubleClicked(LLUICtrl* ctrl, S32 x, S32 y, MASK mask);
+    void onItemClicked(LLUICtrl* ctrl, S32 x, S32 y, MASK mask);
     void updateAvatarNames();
 
 private:
@@ -133,6 +136,7 @@ private:
     bool mShowSpeakingIndicator;
     bool mShowPermissions;
     bool mShowCompleteName;
+    bool mForceCompleteName;
 
     LLTimer*                mLITUpdateTimer; // last interaction time update timer
     std::string             mIconParamName;
@@ -144,6 +148,7 @@ private:
 
     commit_signal_t mRefreshCompleteSignal;
     mouse_signal_t mItemDoubleClickSignal;
+    mouse_signal_t mItemClickedSignal;
 };
 
 /** Abstract comparator for avatar items */
diff --git a/indra/newview/llavatarlistitem.cpp b/indra/newview/llavatarlistitem.cpp
index 7be4f4eeb8..1db7d63309 100644
--- a/indra/newview/llavatarlistitem.cpp
+++ b/indra/newview/llavatarlistitem.cpp
@@ -80,6 +80,7 @@ LLAvatarListItem::LLAvatarListItem(bool not_from_ui_factory/* = true*/)
     mShowProfileBtn(true),
     mShowPermissions(false),
     mShowCompleteName(false),
+    mForceCompleteName(false),
     mHovered(false),
     mAvatarNameCacheConnection(),
     mGreyOutUsername("")
@@ -350,13 +351,11 @@ void LLAvatarListItem::setShowProfileBtn(bool show)
 
 void LLAvatarListItem::showSpeakingIndicator(bool visible)
 {
-    // Already done? Then do nothing.
-    if (mSpeakingIndicator->getVisible() == (bool)visible)
-        return;
-// Disabled to not contradict with SpeakingIndicatorManager functionality. EXT-3976
-// probably this method should be totally removed.
-//  mSpeakingIndicator->setVisible(visible);
-//  updateChildren();
+    if (mSpeakingIndicator)
+    {
+        mSpeakingIndicator->setIsActiveChannel(visible);
+        mSpeakingIndicator->setShowParticipantsSpeaking(visible);
+    }
 }
 
 void LLAvatarListItem::setAvatarIconVisible(bool visible)
@@ -443,8 +442,8 @@ void LLAvatarListItem::onAvatarNameCache(const LLAvatarName& av_name)
     mAvatarNameCacheConnection.disconnect();
 
     mGreyOutUsername = "";
-    std::string name_string = mShowCompleteName? av_name.getCompleteName(false) : av_name.getDisplayName();
-    if(av_name.getCompleteName() != av_name.getUserName())
+    std::string name_string = mShowCompleteName? av_name.getCompleteName(false, mForceCompleteName) : av_name.getDisplayName();
+    if(av_name.getCompleteName(false, mForceCompleteName) != av_name.getUserName())
     {
         mGreyOutUsername = "[ " + av_name.getUserName(true) + " ]";
         LLStringUtil::toLower(mGreyOutUsername);
diff --git a/indra/newview/llavatarlistitem.h b/indra/newview/llavatarlistitem.h
index 630a7ec751..f9381f95e3 100644
--- a/indra/newview/llavatarlistitem.h
+++ b/indra/newview/llavatarlistitem.h
@@ -110,7 +110,7 @@ public:
     void showAvatarDistance(bool show);
     void showLastInteractionTime(bool show);
     void setAvatarIconVisible(bool visible);
-    void setShowCompleteName(bool show) { mShowCompleteName = show;};
+    void setShowCompleteName(bool show, bool force = false) { mShowCompleteName = show; mForceCompleteName = force;};
 
     const LLUUID& getAvatarId() const;
     std::string getAvatarName() const;
@@ -228,6 +228,7 @@ private:
     bool mHovered;
 
     bool mShowCompleteName;
+    bool mForceCompleteName;
     std::string mGreyOutUsername;
 
     void fetchAvatarName();
diff --git a/indra/newview/llfloaterbulkpermission.cpp b/indra/newview/llfloaterbulkpermission.cpp
index c09c02d32b..74c5079268 100644
--- a/indra/newview/llfloaterbulkpermission.cpp
+++ b/indra/newview/llfloaterbulkpermission.cpp
@@ -89,9 +89,17 @@ bool LLFloaterBulkPermission::postBuild()
     {
         mBulkChangeNextOwnerTransfer = true;
     }
+
+    mQueueOutputList = getChild<LLScrollListCtrl>("queue output");
     return true;
 }
 
+void LLFloaterBulkPermission::onClose(bool app_quitting)
+{
+    removeVOInventoryListener();
+    LLFloater::onClose(app_quitting);
+}
+
 void LLFloaterBulkPermission::doApply()
 {
     // Inspects a stream of selected object contents and adds modifiable ones to the given array.
@@ -216,7 +224,7 @@ void LLFloaterBulkPermission::onCommitCopy()
 bool LLFloaterBulkPermission::start()
 {
     // note: number of top-level objects to modify is mObjectIDs.size().
-    getChild<LLScrollListCtrl>("queue output")->setCommentText(getString("start_text"));
+    mQueueOutputList->setCommentText(getString("start_text"));
     return nextObject();
 }
 
@@ -239,7 +247,7 @@ bool LLFloaterBulkPermission::nextObject()
 
     if(isDone() && !mDone)
     {
-        getChild<LLScrollListCtrl>("queue output")->setCommentText(getString("done_text"));
+        mQueueOutputList->setCommentText(getString("done_text"));
         mDone = true;
     }
     return successful_start;
@@ -294,8 +302,6 @@ void LLFloaterBulkPermission::doCheckUncheckAll(bool check)
 
 void LLFloaterBulkPermission::handleInventory(LLViewerObject* viewer_obj, LLInventoryObject::object_list_t* inv)
 {
-    LLScrollListCtrl* list = getChild<LLScrollListCtrl>("queue output");
-
     LLInventoryObject::object_list_t::const_iterator it = inv->begin();
     LLInventoryObject::object_list_t::const_iterator end = inv->end();
     for ( ; it != end; ++it)
@@ -362,7 +368,7 @@ void LLFloaterBulkPermission::handleInventory(LLViewerObject* viewer_obj, LLInve
                     status_text.setArg("[STATUS]", "");
                 }
 
-                list->setCommentText(status_text.getString());
+                mQueueOutputList->setCommentText(status_text.getString());
 
                 //TODO if we are an object inside an object we should check a recuse flag and if set
                 //open the inventory of the object and recurse - Michelle2 Zenovka
diff --git a/indra/newview/llfloaterbulkpermission.h b/indra/newview/llfloaterbulkpermission.h
index 23ca45b611..0b61022e0c 100644
--- a/indra/newview/llfloaterbulkpermission.h
+++ b/indra/newview/llfloaterbulkpermission.h
@@ -41,7 +41,8 @@ class LLFloaterBulkPermission : public LLFloater, public LLVOInventoryListener
     friend class LLFloaterReg;
 public:
 
-    bool postBuild();
+    bool postBuild() override;
+    void onClose(bool app_quitting) override;
 
 private:
 
@@ -57,7 +58,7 @@ private:
     /*virtual*/ void inventoryChanged(LLViewerObject* obj,
                                  LLInventoryObject::object_list_t* inv,
                                  S32 serial_num,
-                                 void* queue);
+                                 void* queue) override;
 
     // This is called by inventoryChanged
     void handleInventory(LLViewerObject* viewer_obj,
@@ -85,7 +86,7 @@ private:
 
 private:
     // UI
-    LLScrollListCtrl* mMessages;
+    LLScrollListCtrl* mQueueOutputList = nullptr;
     LLButton* mCloseBtn;
 
     // Object Queue
diff --git a/indra/newview/llfloaterchatmentionpicker.cpp b/indra/newview/llfloaterchatmentionpicker.cpp
new file mode 100644
index 0000000000..1cfed122a9
--- /dev/null
+++ b/indra/newview/llfloaterchatmentionpicker.cpp
@@ -0,0 +1,184 @@
+/**
+ * @file llfloaterchatmentionpicker.cpp
+ *
+ * $LicenseInfo:firstyear=2025&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2025, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#include "llviewerprecompiledheaders.h"
+
+#include "llfloaterchatmentionpicker.h"
+
+#include "llavatarlist.h"
+#include "llfloaterimcontainer.h"
+#include "llchatmentionhelper.h"
+#include "llparticipantlist.h"
+
+LLUUID LLFloaterChatMentionPicker::sSessionID(LLUUID::null);
+
+LLFloaterChatMentionPicker::LLFloaterChatMentionPicker(const LLSD& key)
+: LLFloater(key), mAvatarList(NULL)
+{
+    // This floater should hover on top of our dependent (with the dependent having the focus)
+    setFocusStealsFrontmost(false);
+    setBackgroundVisible(false);
+    setAutoFocus(false);
+}
+
+bool LLFloaterChatMentionPicker::postBuild()
+{
+    mAvatarList = getChild<LLAvatarList>("avatar_list");
+    mAvatarList->setShowCompleteName(true, true);
+    mAvatarList->setFocusOnItemClicked(false);
+    mAvatarList->setItemClickedCallback([this](LLUICtrl* ctrl, S32 x, S32 y, MASK mask)
+    {
+        if (LLAvatarListItem* item = dynamic_cast<LLAvatarListItem*>(ctrl))
+        {
+            selectResident(item->getAvatarId());
+        }
+    });
+    mAvatarList->setRefreshCompleteCallback([this](LLUICtrl* ctrl, const LLSD& param)
+    {
+        if (mAvatarList->numSelected() == 0)
+        {
+            mAvatarList->selectFirstItem();
+        }
+    });
+
+    return LLFloater::postBuild();
+}
+
+void LLFloaterChatMentionPicker::onOpen(const LLSD& key)
+{
+    buildAvatarList();
+    mAvatarList->setNameFilter(key.has("av_name") ? key["av_name"].asString() : "");
+
+    gFloaterView->adjustToFitScreen(this, false);
+}
+
+uuid_vec_t LLFloaterChatMentionPicker::getParticipantIds()
+{
+    LLParticipantList* item = dynamic_cast<LLParticipantList*>(LLFloaterIMContainer::getInstance()->getSessionModel(sSessionID));
+    if (!item)
+    {
+        LL_WARNS() << "Participant list is missing" << LL_ENDL;
+        return {};
+    }
+
+    uuid_vec_t avatar_ids;
+    LLFolderViewModelItemCommon::child_list_t::const_iterator current_participant_model = item->getChildrenBegin();
+    LLFolderViewModelItemCommon::child_list_t::const_iterator end_participant_model = item->getChildrenEnd();
+    while (current_participant_model != end_participant_model)
+    {
+        LLConversationItem* participant_model = dynamic_cast<LLConversationItem*>(*current_participant_model);
+        if (participant_model)
+        {
+            avatar_ids.push_back(participant_model->getUUID());
+        }
+        current_participant_model++;
+    }
+    return avatar_ids;
+}
+
+void LLFloaterChatMentionPicker::buildAvatarList()
+{
+    uuid_vec_t& avatar_ids = mAvatarList->getIDs();
+    avatar_ids = getParticipantIds();
+    updateAvatarList(avatar_ids);
+    mAvatarList->setDirty();
+}
+
+void LLFloaterChatMentionPicker::selectResident(const LLUUID& id)
+{
+    if (id.isNull())
+        return;
+
+    setValue(stringize("secondlife:///app/agent/", id.asString(), "/mention "));
+    onCommit();
+    LLChatMentionHelper::instance().hideHelper();
+}
+
+void LLFloaterChatMentionPicker::onClose(bool app_quitting)
+{
+    if (!app_quitting)
+    {
+        LLChatMentionHelper::instance().hideHelper();
+    }
+}
+
+bool LLFloaterChatMentionPicker::handleKey(KEY key, MASK mask, bool called_from_parent)
+{
+    if (mask == MASK_NONE)
+    {
+        switch (key)
+        {
+            case KEY_UP:
+            case KEY_DOWN:
+                return mAvatarList->handleKey(key, mask, called_from_parent);
+            case KEY_RETURN:
+            case KEY_TAB:
+                selectResident(mAvatarList->getSelectedUUID());
+                return true;
+            case KEY_ESCAPE:
+                LLChatMentionHelper::instance().hideHelper();
+                return true;
+            case KEY_LEFT:
+            case KEY_RIGHT:
+                return true;
+            default:
+                break;
+        }
+    }
+    return LLFloater::handleKey(key, mask, called_from_parent);
+}
+
+void LLFloaterChatMentionPicker::goneFromFront()
+{
+    LLChatMentionHelper::instance().hideHelper();
+}
+
+void LLFloaterChatMentionPicker::updateSessionID(LLUUID session_id)
+{
+    sSessionID = session_id;
+
+    LLParticipantList* item = dynamic_cast<LLParticipantList*>(LLFloaterIMContainer::getInstance()->getSessionModel(sSessionID));
+    if (!item)
+    {
+        LL_WARNS() << "Participant list is missing" << LL_ENDL;
+        return;
+    }
+
+    uuid_vec_t avatar_ids = getParticipantIds();
+    updateAvatarList(avatar_ids);
+}
+
+void LLFloaterChatMentionPicker::updateAvatarList(uuid_vec_t& avatar_ids)
+{
+    std::vector<std::string> av_names;
+    for (auto& id : avatar_ids)
+    {
+        LLAvatarName av_name;
+        LLAvatarNameCache::get(id, &av_name);
+        av_names.push_back(utf8str_tolower(av_name.getAccountName()));
+        av_names.push_back(utf8str_tolower(av_name.getDisplayName()));
+    }
+    LLChatMentionHelper::instance().updateAvatarList(av_names);
+}
diff --git a/indra/newview/llfloaterchatmentionpicker.h b/indra/newview/llfloaterchatmentionpicker.h
new file mode 100644
index 0000000000..8d221d7a89
--- /dev/null
+++ b/indra/newview/llfloaterchatmentionpicker.h
@@ -0,0 +1,58 @@
+/**
+ * @file llfloaterchatmentionpicker.h
+ *
+ * $LicenseInfo:firstyear=2025&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2025, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#ifndef LLFLOATERCHATMENTIONPICKER_H
+#define LLFLOATERCHATMENTIONPICKER_H
+
+#include "llfloater.h"
+
+class LLAvatarList;
+
+class LLFloaterChatMentionPicker : public LLFloater
+{
+public:
+    LLFloaterChatMentionPicker(const LLSD& key);
+
+    virtual bool postBuild() override;
+    virtual void goneFromFront() override;
+
+    void buildAvatarList();
+
+    static uuid_vec_t getParticipantIds();
+    static void updateSessionID(LLUUID session_id);
+    static void updateAvatarList(uuid_vec_t& avatar_ids);
+
+private:
+
+    void onOpen(const LLSD& key) override;
+    void onClose(bool app_quitting) override;
+    virtual bool handleKey(KEY key, MASK mask, bool called_from_parent) override;
+    void selectResident(const LLUUID& id);
+
+    static LLUUID sSessionID;
+    LLAvatarList* mAvatarList;
+};
+
+#endif
diff --git a/indra/newview/llfloaterimnearbychat.cpp b/indra/newview/llfloaterimnearbychat.cpp
index db6f9ac22a..b649514bff 100644
--- a/indra/newview/llfloaterimnearbychat.cpp
+++ b/indra/newview/llfloaterimnearbychat.cpp
@@ -586,7 +586,7 @@ void LLFloaterIMNearbyChat::sendChat( EChatType type )
 {
     if (mInputEditor)
     {
-        LLWString text = mInputEditor->getWText();
+        LLWString text = mInputEditor->getConvertedText();
         LLWStringUtil::trim(text);
         LLWStringUtil::replaceChar(text,182,'\n'); // Convert paragraph symbols back into newlines.
         if (!text.empty())
diff --git a/indra/newview/llfloaterimsession.cpp b/indra/newview/llfloaterimsession.cpp
index 185274981b..84a9fad708 100644
--- a/indra/newview/llfloaterimsession.cpp
+++ b/indra/newview/llfloaterimsession.cpp
@@ -251,7 +251,7 @@ void LLFloaterIMSession::sendMsgFromInputEditor()
     {
         if (mInputEditor)
         {
-            LLWString text = mInputEditor->getWText();
+            LLWString text = mInputEditor->getConvertedText();
             LLWStringUtil::trim(text);
             LLWStringUtil::replaceChar(text,182,'\n'); // Convert paragraph symbols back into newlines.
             if(!text.empty())
diff --git a/indra/newview/llfloaterimsessiontab.cpp b/indra/newview/llfloaterimsessiontab.cpp
index 553aa1ff4b..cd428c67ef 100644
--- a/indra/newview/llfloaterimsessiontab.cpp
+++ b/indra/newview/llfloaterimsessiontab.cpp
@@ -35,6 +35,7 @@
 #include "llavatariconctrl.h"
 #include "llchatentry.h"
 #include "llchathistory.h"
+#include "llfloaterchatmentionpicker.h"
 #include "llchiclet.h"
 #include "llchicletbar.h"
 #include "lldraghandle.h"
@@ -485,6 +486,7 @@ void LLFloaterIMSessionTab::onFocusReceived()
         LLIMModel::instance().sendNoUnreadMessages(mSessionID);
     }
 
+    LLFloaterChatMentionPicker::updateSessionID(mSessionID);
     super::onFocusReceived();
 }
 
diff --git a/indra/newview/llfloaternewfeaturenotification.cpp b/indra/newview/llfloaternewfeaturenotification.cpp
index 369727ff1e..1badcdd3d9 100644
--- a/indra/newview/llfloaternewfeaturenotification.cpp
+++ b/indra/newview/llfloaternewfeaturenotification.cpp
@@ -43,12 +43,28 @@ bool LLFloaterNewFeatureNotification::postBuild()
     setCanDrag(false);
     getChild<LLButton>("close_btn")->setCommitCallback(boost::bind(&LLFloaterNewFeatureNotification::onCloseBtn, this));
 
-    const std::string title_txt = "title_txt";
-    const std::string dsc_txt = "description_txt";
-    std::string feature = "_" + getKey().asString();
+    if (getKey().isString())
+    {
+        const std::string title_txt = "title_txt";
+        const std::string dsc_txt = "description_txt";
 
-    getChild<LLUICtrl>(title_txt)->setValue(getString(title_txt + feature));
-    getChild<LLUICtrl>(dsc_txt)->setValue(getString(dsc_txt + feature));
+        std::string feature = "_" + getKey().asString();
+        if (hasString(title_txt + feature))
+        {
+            getChild<LLUICtrl>(title_txt)->setValue(getString(title_txt + feature));
+            getChild<LLUICtrl>(dsc_txt)->setValue(getString(dsc_txt + feature));
+        }
+        else
+        {
+            // Show blank
+            LL_WARNS() << "Feature \"" << getKey().asString() <<  "\" not found for feature notification" << LL_ENDL;
+        }
+    }
+    else
+    {
+        // Show blank
+        LL_WARNS() << "Feature notification without a feature" << LL_ENDL;
+    }
 
     if (getKey().asString() == "gltf")
     {
diff --git a/indra/newview/llinventorymodel.cpp b/indra/newview/llinventorymodel.cpp
index de1c7a7ed8..c9e9d50e19 100644
--- a/indra/newview/llinventorymodel.cpp
+++ b/indra/newview/llinventorymodel.cpp
@@ -2768,6 +2768,7 @@ bool LLInventoryModel::loadSkeleton(
         bool is_cache_obsolete = false;
         if (loadFromFile(inventory_filename, categories, items, categories_to_update, is_cache_obsolete))
         {
+            LL_PROFILE_ZONE_NAMED("loadFromFile");
             // We were able to find a cache of files. So, use what we
             // found to generate a set of categories we should add. We
             // will go through each category loaded and if the version
diff --git a/indra/newview/llmeshrepository.cpp b/indra/newview/llmeshrepository.cpp
index 48c80842b9..851107b3be 100644
--- a/indra/newview/llmeshrepository.cpp
+++ b/indra/newview/llmeshrepository.cpp
@@ -544,6 +544,66 @@ bool RequestStats::isDelayed() const
     return mTimer.getStarted() && !mTimer.hasExpired();
 }
 
+F32 calculate_score(LLVOVolume* object)
+{
+    if (!object)
+    {
+        return -1.f;
+    }
+    LLDrawable* drawable = object->mDrawable;
+    if (!drawable)
+    {
+        return -1;
+    }
+    if (drawable->isState(LLDrawable::RIGGED) || object->isAttachment())
+    {
+        LLVOAvatar* avatar = object->getAvatar();
+        LLDrawable* av_drawable = avatar ? avatar->mDrawable : nullptr;
+        if (avatar && av_drawable)
+        {
+            // See LLVOVolume::calcLOD()
+            F32 radius;
+            if (avatar->isControlAvatar())
+            {
+                const LLVector3* box = avatar->getLastAnimExtents();
+                LLVector3 diag = box[1] - box[0];
+                radius = diag.magVec() * 0.5f;
+            }
+            else
+            {
+                // Volume in a rigged mesh attached to a regular avatar.
+                const LLVector3* box = avatar->getLastAnimExtents();
+                LLVector3 diag = box[1] - box[0];
+                radius = diag.magVec();
+
+                if (!avatar->isSelf() && !avatar->hasFirstFullAttachmentData())
+                {
+                    // slightly deprioritize avatars that are still receiving data
+                    radius *= 0.9f;
+                }
+            }
+            return radius / llmax(av_drawable->mDistanceWRTCamera, 1.f);
+        }
+    }
+    return drawable->getRadius() / llmax(drawable->mDistanceWRTCamera, 1.f);
+}
+
+void PendingRequestBase::updateScore()
+{
+    mScore = 0;
+    if (mTrackedData)
+    {
+        for (LLVOVolume* volume : mTrackedData->mVolumes)
+        {
+            F32 cur_score = calculate_score(volume);
+            if (cur_score > 0)
+            {
+                mScore = llmax(mScore, cur_score);
+            }
+        }
+    }
+}
+
 LLViewerFetchedTexture* LLMeshUploadThread::FindViewerTexture(const LLImportMaterial& material)
 {
     LLPointer< LLViewerFetchedTexture > * ppTex = static_cast< LLPointer< LLViewerFetchedTexture > * >(material.mOpaqueData);
@@ -1809,42 +1869,36 @@ bool LLMeshRepoThread::fetchMeshPhysicsShape(const LLUUID& mesh_id)
 //static
 void LLMeshRepoThread::incActiveLODRequests()
 {
-    LLMutexLock lock(gMeshRepo.mThread->mMutex);
     ++LLMeshRepoThread::sActiveLODRequests;
 }
 
 //static
 void LLMeshRepoThread::decActiveLODRequests()
 {
-    LLMutexLock lock(gMeshRepo.mThread->mMutex);
     --LLMeshRepoThread::sActiveLODRequests;
 }
 
 //static
 void LLMeshRepoThread::incActiveHeaderRequests()
 {
-    LLMutexLock lock(gMeshRepo.mThread->mMutex);
     ++LLMeshRepoThread::sActiveHeaderRequests;
 }
 
 //static
 void LLMeshRepoThread::decActiveHeaderRequests()
 {
-    LLMutexLock lock(gMeshRepo.mThread->mMutex);
     --LLMeshRepoThread::sActiveHeaderRequests;
 }
 
 //static
 void LLMeshRepoThread::incActiveSkinRequests()
 {
-    LLMutexLock lock(gMeshRepo.mThread->mMutex);
     ++LLMeshRepoThread::sActiveSkinRequests;
 }
 
 //static
 void LLMeshRepoThread::decActiveSkinRequests()
 {
-    LLMutexLock lock(gMeshRepo.mThread->mMutex);
     --LLMeshRepoThread::sActiveSkinRequests;
 }
 
@@ -2226,7 +2280,7 @@ EMeshProcessingResult LLMeshRepoThread::headerReceived(const LLVolumeParams& mes
 
                 if (gMeshRepo.mLoadingSkins.find(mesh_id) == gMeshRepo.mLoadingSkins.end())
                 {
-                    gMeshRepo.mLoadingSkins[mesh_id] = {}; // add an empty vector to indicate to main thread that we are loading skin info
+                    gMeshRepo.mLoadingSkins[mesh_id]; // add an empty vector to indicate to main thread that we are loading skin info
                 }
             }
 
@@ -4218,13 +4272,13 @@ void LLMeshRepository::unregisterMesh(LLVOVolume* vobj)
     {
         for (auto& param : lod)
         {
-            vector_replace_with_last(param.second, vobj);
+            vector_replace_with_last(param.second.mVolumes, vobj);
         }
     }
 
     for (auto& skin_pair : mLoadingSkins)
     {
-        vector_replace_with_last(skin_pair.second, vobj);
+        vector_replace_with_last(skin_pair.second.mVolumes, vobj);
     }
 }
 
@@ -4247,16 +4301,17 @@ S32 LLMeshRepository::loadMesh(LLVOVolume* vobj, const LLVolumeParams& mesh_para
         mesh_load_map::iterator iter = mLoadingMeshes[new_lod].find(mesh_id);
         if (iter != mLoadingMeshes[new_lod].end())
         { //request pending for this mesh, append volume id to list
-            auto it = std::find(iter->second.begin(), iter->second.end(), vobj);
-            if (it == iter->second.end()) {
-                iter->second.push_back(vobj);
+            auto it = std::find(iter->second.mVolumes.begin(), iter->second.mVolumes.end(), vobj);
+            if (it == iter->second.mVolumes.end()) {
+                iter->second.addVolume(vobj);
             }
         }
         else
         {
             //first request for this mesh
-            mLoadingMeshes[new_lod][mesh_id].push_back(vobj);
-            mPendingRequests.emplace_back(new PendingRequestLOD(mesh_params, new_lod));
+            std::shared_ptr<PendingRequestBase> request(new PendingRequestLOD(mesh_params, new_lod));
+            mPendingRequests.emplace_back(request);
+            mLoadingMeshes[new_lod][mesh_id].initData(vobj, request);
             LLMeshRepository::sLODPending++;
         }
     }
@@ -4315,50 +4370,6 @@ S32 LLMeshRepository::loadMesh(LLVOVolume* vobj, const LLVolumeParams& mesh_para
     return new_lod;
 }
 
-F32 calculate_score(LLVOVolume* object)
-{
-    if (!object)
-    {
-        return -1.f;
-    }
-    LLDrawable* drawable = object->mDrawable;
-    if (!drawable)
-    {
-        return -1;
-    }
-    if (drawable->isState(LLDrawable::RIGGED) || object->isAttachment())
-    {
-        LLVOAvatar* avatar = object->getAvatar();
-        LLDrawable* av_drawable = avatar ? avatar->mDrawable : nullptr;
-        if (avatar && av_drawable)
-        {
-            // See LLVOVolume::calcLOD()
-            F32 radius;
-            if (avatar->isControlAvatar())
-            {
-                const LLVector3* box = avatar->getLastAnimExtents();
-                LLVector3 diag = box[1] - box[0];
-                radius = diag.magVec() * 0.5f;
-            }
-            else
-            {
-                // Volume in a rigged mesh attached to a regular avatar.
-                const LLVector3* box = avatar->getLastAnimExtents();
-                LLVector3 diag = box[1] - box[0];
-                radius = diag.magVec();
-
-                if (!avatar->isSelf() && !avatar->hasFirstFullAttachmentData())
-                {
-                    // slightly deprioritize avatars that are still receiving data
-                    radius *= 0.9f;
-                }
-            }
-            return radius / llmax(av_drawable->mDistanceWRTCamera, 1.f);
-        }
-    }
-    return drawable->getRadius() / llmax(drawable->mDistanceWRTCamera, 1.f);
-}
-
 void LLMeshRepository::notifyLoadedMeshes()
 { //called from main thread
     LL_PROFILE_ZONE_SCOPED_CATEGORY_NETWORK; //LL_RECORD_BLOCK_TIME(FTM_MESH_FETCH);
@@ -4495,13 +4506,20 @@ void LLMeshRepository::notifyLoadedMeshes()
     {
         LLMutexTrylock lock1(mMeshMutex);
         LLMutexTrylock lock2(mThread->mMutex);
+        LLMutexTrylock lock3(mThread->mHeaderMutex);
+        LLMutexTrylock lock4(mThread->mPendingMutex);
 
         static U32 hold_offs(0);
-        if (! lock1.isLocked() || ! lock2.isLocked())
+        if (! lock1.isLocked() || ! lock2.isLocked() || ! lock3.isLocked() || ! lock4.isLocked())
         {
             // If we can't get the locks, skip and pick this up later.
+            // Eventually thread queue will be free enough
             ++hold_offs;
             sMaxLockHoldoffs = llmax(sMaxLockHoldoffs, hold_offs);
+            if (hold_offs > 4)
+            {
+                LL_WARNS_ONCE() << "High mesh thread holdoff" << LL_ENDL;
+            }
             return;
         }
         hold_offs = 0;
@@ -4548,61 +4566,25 @@ void LLMeshRepository::notifyLoadedMeshes()
 
             if (mPendingRequests.size() > push_count)
             {
+                LL_PROFILE_ZONE_NAMED("Mesh score update");
                 // More requests than the high-water limit allows so
                 // sort and forward the most important.
 
-                //calculate "score" for pending requests
-
-                //create score map
-                std::map<LLUUID, F32> score_map;
-
-                for (U32 i = 0; i < LLVolumeLODGroup::NUM_LODS; ++i)
-                {
-                    for (mesh_load_map::iterator iter = mLoadingMeshes[i].begin();  iter != mLoadingMeshes[i].end(); ++iter)
-                    {
-                        F32 max_score = 0.f;
-                        for (auto obj_iter = iter->second.begin(); obj_iter != iter->second.end(); ++obj_iter)
-                        {
-                            F32 cur_score = calculate_score(*obj_iter);
-                            if (cur_score >= 0.f)
-                            {
-                                max_score = llmax(max_score, cur_score);
-                            }
-                        }
-
-                        score_map[iter->first] = max_score;
-                    }
-                }
-                for (mesh_load_map::iterator iter = mLoadingSkins.begin(); iter != mLoadingSkins.end(); ++iter)
-                {
-                    F32 max_score = 0.f;
-                    for (auto obj_iter = iter->second.begin(); obj_iter != iter->second.end(); ++obj_iter)
-                    {
-                        F32 cur_score = calculate_score(*obj_iter);
-                        if (cur_score >= 0.f)
-                        {
-                            max_score = llmax(max_score, cur_score);
-                        }
-                    }
-
-                    score_map[iter->first] = max_score;
-                }
-
-                //set "score" for pending requests
-                for (std::unique_ptr<PendingRequestBase>& req_p : mPendingRequests)
+                // update "score" for pending requests
+                for (std::shared_ptr<PendingRequestBase>& req_p : mPendingRequests)
                 {
-                    req_p->setScore(score_map[req_p->getId()]);
+                    req_p->checkScore();
                 }
 
                 //sort by "score"
                 std::partial_sort(mPendingRequests.begin(), mPendingRequests.begin() + push_count,
                                   mPendingRequests.end(), PendingRequestBase::CompareScoreGreater());
             }
-            LLMutexTrylock lock3(mThread->mHeaderMutex);
-            LLMutexTrylock lock4(mThread->mPendingMutex);
             while (!mPendingRequests.empty() && push_count > 0)
             {
-                std::unique_ptr<PendingRequestBase>& req_p = mPendingRequests.front();
+                std::shared_ptr<PendingRequestBase>& req_p = mPendingRequests.front();
+                // todo: check hasTrackedData here and erase request if none
+                // since this is supposed to mean that request was removed
                 switch (req_p->getRequestType())
                 {
                 case MESH_REQUEST_LOD:
@@ -4657,7 +4639,7 @@ void LLMeshRepository::notifySkinInfoReceived(LLMeshSkinInfo* info)
     skin_load_map::iterator iter = mLoadingSkins.find(info->mMeshID);
     if (iter != mLoadingSkins.end())
     {
-        for (LLVOVolume* vobj : iter->second)
+        for (LLVOVolume* vobj : iter->second.mVolumes)
         {
             if (vobj)
             {
@@ -4673,7 +4655,7 @@ void LLMeshRepository::notifySkinInfoUnavailable(const LLUUID& mesh_id)
     skin_load_map::iterator iter = mLoadingSkins.find(mesh_id);
     if (iter != mLoadingSkins.end())
     {
-        for (LLVOVolume* vobj : iter->second)
+        for (LLVOVolume* vobj : iter->second.mVolumes)
         {
             if (vobj)
             {
@@ -4737,7 +4719,7 @@ void LLMeshRepository::notifyMeshLoaded(const LLVolumeParams& mesh_params, LLVol
         }
 
         //notify waiting LLVOVolume instances that their requested mesh is available
-        for (LLVOVolume* vobj : obj_iter->second)
+        for (LLVOVolume* vobj : obj_iter->second.mVolumes)
         {
             if (vobj)
             {
@@ -4767,7 +4749,7 @@ void LLMeshRepository::notifyMeshUnavailable(const LLVolumeParams& mesh_params,
             LLPrimitive::getVolumeManager()->unrefVolume(sys_volume);
         }
 
-        for (LLVOVolume* vobj : obj_iter->second)
+        for (LLVOVolume* vobj : obj_iter->second.mVolumes)
         {
             if (vobj)
             {
@@ -4810,16 +4792,17 @@ const LLMeshSkinInfo* LLMeshRepository::getSkinInfo(const LLUUID& mesh_id, LLVOV
             skin_load_map::iterator iter = mLoadingSkins.find(mesh_id);
             if (iter != mLoadingSkins.end())
             { //request pending for this mesh, append volume id to list
-                auto it = std::find(iter->second.begin(), iter->second.end(), requesting_obj);
-                if (it == iter->second.end()) {
-                    iter->second.push_back(requesting_obj);
+                auto it = std::find(iter->second.mVolumes.begin(), iter->second.mVolumes.end(), requesting_obj);
+                if (it == iter->second.mVolumes.end()) {
+                    iter->second.addVolume(requesting_obj);
                 }
             }
             else
             {
                 //first request for this mesh
-                mLoadingSkins[mesh_id].push_back(requesting_obj);
-                mPendingRequests.emplace_back(new PendingRequestUUID(mesh_id, MESH_REQUEST_SKIN));
+                std::shared_ptr<PendingRequestBase> request(new PendingRequestUUID(mesh_id, MESH_REQUEST_SKIN));
+                mLoadingSkins[mesh_id].initData(requesting_obj, request);
+                mPendingRequests.emplace_back(request);
             }
         }
     }
diff --git a/indra/newview/llmeshrepository.h b/indra/newview/llmeshrepository.h
index b9acb3573f..0847c29d0d 100644
--- a/indra/newview/llmeshrepository.h
+++ b/indra/newview/llmeshrepository.h
@@ -168,7 +168,6 @@ public:
 
     void submitRequest(Request* request);
     static S32 llcdCallback(const char*, S32, S32);
-    void cancel();
 
     void setMeshData(LLCDMeshData& mesh, bool vertex_based);
     void doDecomposition();
@@ -206,19 +205,19 @@ private:
     LLFrameTimer mTimer;
 };
 
-
+class MeshLoadData;
 class PendingRequestBase
 {
 public:
     struct CompareScoreGreater
     {
-        bool operator()(const std::unique_ptr<PendingRequestBase>& lhs, const std::unique_ptr<PendingRequestBase>& rhs)
+        bool operator()(const std::shared_ptr<PendingRequestBase>& lhs, const std::shared_ptr<PendingRequestBase>& rhs)
         {
             return lhs->mScore > rhs->mScore; // greatest = first
         }
     };
 
-    PendingRequestBase() : mScore(0.f) {};
+    PendingRequestBase() : mScore(0.f), mTrackedData(nullptr), mScoreDirty(true) {};
     virtual ~PendingRequestBase() {}
 
     bool operator<(const PendingRequestBase& rhs) const
@@ -226,14 +225,34 @@ public:
         return mId < rhs.mId;
     }
 
-    void setScore(F32 score) { mScore = score; }
     F32 getScore() const { return mScore; }
+    void checkScore()
+    {
+        constexpr F32 EXPIRE_TIME_SECS = 8.f;
+        if (mScoreTimer.getElapsedTimeF32() > EXPIRE_TIME_SECS || mScoreDirty)
+        {
+            updateScore();
+            mScoreDirty = false;
+            mScoreTimer.reset();
+        }
+    };
+
     LLUUID getId() const { return mId; }
     virtual EMeshRequestType getRequestType() const = 0;
 
+    void trackData(MeshLoadData* data) { mTrackedData = data; mScoreDirty = true; }
+    void untrackData() { mTrackedData = nullptr; }
+    bool hasTrackedData() { return mTrackedData != nullptr; }
+    void setScoreDirty() { mScoreDirty = true; }
+
 protected:
-    F32 mScore;
+    void updateScore();
+
     LLUUID mId;
+    F32 mScore;
+    bool mScoreDirty;
+    LLTimer mScoreTimer;
+    MeshLoadData* mTrackedData;
 };
 
 class PendingRequestLOD : public PendingRequestBase
@@ -267,6 +286,37 @@ private:
     EMeshRequestType mRequestType;
 };
 
+
+class MeshLoadData
+{
+public:
+    MeshLoadData() {}
+    ~MeshLoadData()
+    {
+        if (std::shared_ptr<PendingRequestBase> request = mRequest.lock())
+        {
+            request->untrackData();
+        }
+    }
+    void initData(LLVOVolume* vol, std::shared_ptr<PendingRequestBase>& request)
+    {
+        mVolumes.push_back(vol);
+        request->trackData(this);
+        mRequest = request;
+    }
+    void addVolume(LLVOVolume* vol)
+    {
+        mVolumes.push_back(vol);
+        if (std::shared_ptr<PendingRequestBase> request = mRequest.lock())
+        {
+            request->setScoreDirty();
+        }
+    }
+    std::vector<LLVOVolume*> mVolumes;
+private:
+    std::weak_ptr<PendingRequestBase> mRequest;
+};
+
 class LLMeshHeader
 {
 public:
@@ -814,7 +864,7 @@ public:
     static void metricsProgress(unsigned int count);
     static void metricsUpdate();
 
-    typedef std::unordered_map<LLUUID, std::vector<LLVOVolume*> > mesh_load_map;
+    typedef std::unordered_map<LLUUID, MeshLoadData> mesh_load_map;
     mesh_load_map mLoadingMeshes[4];
 
     typedef std::unordered_map<LLUUID, LLPointer<LLMeshSkinInfo>> skin_map;
@@ -825,11 +875,11 @@ public:
 
     LLMutex*                    mMeshMutex;
 
-    typedef std::vector <std::unique_ptr<PendingRequestBase> > pending_requests_vec;
+    typedef std::vector <std::shared_ptr<PendingRequestBase> > pending_requests_vec;
     pending_requests_vec mPendingRequests;
 
     //list of mesh ids awaiting skin info
-    typedef std::unordered_map<LLUUID, std::vector<LLVOVolume*> > skin_load_map;
+    typedef std::unordered_map<LLUUID, MeshLoadData > skin_load_map;
     skin_load_map mLoadingSkins;
 
     //list of mesh ids awaiting decompositions
diff --git a/indra/newview/llpanelface.cpp b/indra/newview/llpanelface.cpp
index 3a164ec94b..5b059516cd 100644
--- a/indra/newview/llpanelface.cpp
+++ b/indra/newview/llpanelface.cpp
@@ -1106,6 +1106,63 @@ void LLPanelFace::updateUI(bool force_set_values /*false*/)
 
         updateVisibility(objectp);
 
+        bool missing_asset = false;
+        {
+            LLGLenum image_format = GL_RGB;
+            bool identical_image_format = false;
+            LLSelectedTE::getImageFormat(image_format, identical_image_format, missing_asset);
+
+            if (!missing_asset)
+            {
+                mIsAlpha = false;
+                switch (image_format)
+                {
+                    case GL_RGBA:
+                    case GL_ALPHA:
+                    {
+                        mIsAlpha = true;
+                    }
+                    break;
+
+                    case GL_RGB:
+                        break;
+                    default:
+                    {
+                        LL_WARNS() << "Unexpected tex format in LLPanelFace...resorting to no alpha" << LL_ENDL;
+                    }
+                    break;
+                }
+            }
+            else
+            {
+                // Don't know image's properties, use material's mode value
+                mIsAlpha = true;
+            }
+
+            // Diffuse Alpha Mode
+            // Init to the default that is appropriate for the alpha content of the asset
+            //
+            U8 alpha_mode = mIsAlpha ? LLMaterial::DIFFUSE_ALPHA_MODE_BLEND : LLMaterial::DIFFUSE_ALPHA_MODE_NONE;
+
+            bool identical_alpha_mode = false;
+
+            // See if that's been overridden by a material setting for same...
+            //
+            LLSelectedTEMaterial::getCurrentDiffuseAlphaMode(alpha_mode, identical_alpha_mode, mIsAlpha);
+
+            // it is invalid to have any alpha mode other than blend if transparency is greater than zero ...
+            // Want masking? Want emissive? Tough! You get BLEND!
+            alpha_mode = (transparency > 0.f) ? LLMaterial::DIFFUSE_ALPHA_MODE_BLEND : alpha_mode;
+
+            // ... unless there is no alpha channel in the texture, in which case alpha mode MUST be none
+            alpha_mode = mIsAlpha ? alpha_mode : LLMaterial::DIFFUSE_ALPHA_MODE_NONE;
+
+            mComboAlphaMode->getSelectionInterface()->selectNthItem(alpha_mode);
+            updateAlphaControls();
+
+            mExcludeWater &= (LLMaterial::DIFFUSE_ALPHA_MODE_BLEND == alpha_mode);
+        }
+
         // Water exclusion
         {
             mCheckHideWater->setEnabled(editable && !has_pbr_material && !isMediaTexSelected());
@@ -1188,65 +1245,11 @@ void LLPanelFace::updateUI(bool force_set_values /*false*/)
 
         // Texture
         {
-            LLGLenum image_format = GL_RGB;
-            bool identical_image_format = false;
-            bool missing_asset = false;
-            LLSelectedTE::getImageFormat(image_format, identical_image_format, missing_asset);
-
-            if (!missing_asset)
-            {
-                mIsAlpha = false;
-                switch (image_format)
-                {
-                case GL_RGBA:
-                case GL_ALPHA:
-                    {
-                        mIsAlpha = true;
-                    }
-                    break;
-
-                case GL_RGB: break;
-                default:
-                    {
-                        LL_WARNS() << "Unexpected tex format in LLPanelFace...resorting to no alpha" << LL_ENDL;
-                    }
-                    break;
-                }
-            }
-            else
-            {
-                // Don't know image's properties, use material's mode value
-                mIsAlpha = true;
-            }
-
             if (LLViewerMedia::getInstance()->textureHasMedia(id))
             {
                 mBtnAlign->setEnabled(editable);
             }
 
-            // Diffuse Alpha Mode
-
-            // Init to the default that is appropriate for the alpha content of the asset
-            //
-            U8 alpha_mode = mIsAlpha ? LLMaterial::DIFFUSE_ALPHA_MODE_BLEND : LLMaterial::DIFFUSE_ALPHA_MODE_NONE;
-
-            bool identical_alpha_mode = false;
-
-            // See if that's been overridden by a material setting for same...
-            //
-            LLSelectedTEMaterial::getCurrentDiffuseAlphaMode(alpha_mode, identical_alpha_mode, mIsAlpha);
-
-            // it is invalid to have any alpha mode other than blend if transparency is greater than zero ...
-            // Want masking? Want emissive? Tough! You get BLEND!
-            alpha_mode = (transparency > 0.f) ? LLMaterial::DIFFUSE_ALPHA_MODE_BLEND : alpha_mode;
-
-            // ... unless there is no alpha channel in the texture, in which case alpha mode MUST be none
-            alpha_mode = mIsAlpha ? alpha_mode : LLMaterial::DIFFUSE_ALPHA_MODE_NONE;
-
-            mComboAlphaMode->getSelectionInterface()->selectNthItem(alpha_mode);
-
-            updateAlphaControls();
-
             if (mTextureCtrl)
             {
                 if (identical_diffuse)
@@ -4009,6 +4012,85 @@ void LLPanelFace::onPasteColor(LLViewerObject* objectp, S32 te)
     }
 }
 
+void set_item_availability(
+    const LLUUID& id,
+    LLSD& dest,
+    const std::string& modifier,
+    bool is_creator,
+    std::map<LLUUID, LLUUID> &asset_item_map,
+    LLViewerObject* objectp)
+{
+    if (id.isNull())
+    {
+        return;
+    }
+
+    LLUUID item_id;
+    bool from_library = get_is_predefined_texture(id);
+    bool full_perm = from_library;
+    full_perm |= is_creator;
+
+    if (!full_perm)
+    {
+        std::map<LLUUID, LLUUID>::iterator iter = asset_item_map.find(id);
+        if (iter != asset_item_map.end())
+        {
+            item_id = iter->second;
+        }
+        else
+        {
+            // What this does is simply searches inventory for item with same asset id,
+            // as result it is Hightly unreliable, leaves little control to user, borderline hack
+            // but there are little options to preserve permissions - multiple inventory
+            // items might reference same asset and inventory search is expensive.
+            bool no_transfer = false;
+            if (objectp->getInventoryItemByAsset(id))
+            {
+                no_transfer = !objectp->getInventoryItemByAsset(id)->getIsFullPerm();
+            }
+            item_id = get_copy_free_item_by_asset_id(id, no_transfer);
+            // record value to avoid repeating inventory search when possible
+            asset_item_map[id] = item_id;
+        }
+    }
+
+    if (item_id.notNull() && gInventory.isObjectDescendentOf(item_id, gInventory.getLibraryRootFolderID()))
+    {
+        full_perm = true;
+        from_library = true;
+    }
+
+    dest[modifier + "itemfullperm"] = full_perm;
+    dest[modifier + "fromlibrary"] = from_library;
+
+    // If full permission object, texture is free to copy,
+    // but otherwise we need to check inventory and extract permissions
+    //
+    // Normally we care only about restrictions for current user and objects
+    // don't inherit any 'next owner' permissions from texture, so there is
+    // no need to record item id if full_perm==true
+    if (!full_perm && item_id.notNull())
+    {
+        LLViewerInventoryItem* itemp = gInventory.getItem(item_id);
+        if (itemp)
+        {
+            LLPermissions item_permissions = itemp->getPermissions();
+            if (item_permissions.allowOperationBy(PERM_COPY,
+                gAgent.getID(),
+                gAgent.getGroupID()))
+            {
+                dest[modifier + "itemid"] = item_id;
+                dest[modifier + "itemfullperm"] = itemp->getIsFullPerm();
+                if (!itemp->isFinished())
+                {
+                    // needed for dropTextureAllFaces
+                    LLInventoryModelBackgroundFetch::instance().start(item_id, false);
+                }
+            }
+        }
+    }
+}
+
 void LLPanelFace::onCopyTexture()
 {
     LLViewerObject* objectp = LLSelectMgr::getInstance()->getSelection()->getFirstObject();
@@ -4046,6 +4128,7 @@ void LLPanelFace::onCopyTexture()
             if (tep)
             {
                 LLSD te_data;
+                LLUUID pbr_id = objectp->getRenderMaterialID(te);
 
                 // asLLSD() includes media
                 te_data["te"] = tep->asLLSD();
@@ -4054,21 +4137,20 @@ void LLPanelFace::onCopyTexture()
                 te_data["te"]["bumpshiny"] = tep->getBumpShiny();
                 te_data["te"]["bumpfullbright"] = tep->getBumpShinyFullbright();
                 te_data["te"]["texgen"] = tep->getTexGen();
-                te_data["te"]["pbr"] = objectp->getRenderMaterialID(te);
+                te_data["te"]["pbr"] = pbr_id;
                 if (tep->getGLTFMaterialOverride() != nullptr)
                 {
                     te_data["te"]["pbr_override"] = tep->getGLTFMaterialOverride()->asJSON();
                 }
 
-                if (te_data["te"].has("imageid"))
+                if (te_data["te"].has("imageid") || pbr_id.notNull())
                 {
-                    LLUUID item_id;
-                    LLUUID id = te_data["te"]["imageid"].asUUID();
-                    bool from_library = get_is_predefined_texture(id);
-                    bool full_perm = from_library;
+                    LLUUID img_id = te_data["te"]["imageid"].asUUID();
+                    bool pbr_from_library = false;
+                    bool pbr_full_perm = false;
+                    bool is_creator = false;
 
-                    if (!full_perm
-                        && objectp->permCopy()
+                    if (objectp->permCopy()
                         && objectp->permTransfer()
                         && objectp->permModify())
                     {
@@ -4078,66 +4160,31 @@ void LLPanelFace::onCopyTexture()
                         std::string creator_app_link;
                         LLUUID creator_id;
                         LLSelectMgr::getInstance()->selectGetCreator(creator_id, creator_app_link);
-                        full_perm = objectp->mOwnerID == creator_id;
+                        is_creator = objectp->mOwnerID == creator_id;
                     }
 
-                    if (id.notNull() && !full_perm)
+                    // check permissions for blin-phong/diffuse image and for pbr asset
+                    if (img_id.notNull())
                     {
-                        std::map<LLUUID, LLUUID>::iterator iter = asset_item_map.find(id);
-                        if (iter != asset_item_map.end())
-                        {
-                            item_id = iter->second;
-                        }
-                        else
-                        {
-                            // What this does is simply searches inventory for item with same asset id,
-                            // as result it is Hightly unreliable, leaves little control to user, borderline hack
-                            // but there are little options to preserve permissions - multiple inventory
-                            // items might reference same asset and inventory search is expensive.
-                            bool no_transfer = false;
-                            if (objectp->getInventoryItemByAsset(id))
-                            {
-                                no_transfer = !objectp->getInventoryItemByAsset(id)->getIsFullPerm();
-                            }
-                            item_id = get_copy_free_item_by_asset_id(id, no_transfer);
-                            // record value to avoid repeating inventory search when possible
-                            asset_item_map[id] = item_id;
-                        }
+                        set_item_availability(img_id, te_data["te"], "img", is_creator, asset_item_map, objectp);
                     }
-
-                    if (item_id.notNull() && gInventory.isObjectDescendentOf(item_id, gInventory.getLibraryRootFolderID()))
+                    if (pbr_id.notNull())
                     {
-                        full_perm = true;
-                        from_library = true;
-                    }
+                        set_item_availability(pbr_id, te_data["te"], "pbr", is_creator, asset_item_map, objectp);
 
-                    {
-                        te_data["te"]["itemfullperm"] = full_perm;
-                        te_data["te"]["fromlibrary"] = from_library;
-
-                        // If full permission object, texture is free to copy,
-                        // but otherwise we need to check inventory and extract permissions
-                        //
-                        // Normally we care only about restrictions for current user and objects
-                        // don't inherit any 'next owner' permissions from texture, so there is
-                        // no need to record item id if full_perm==true
-                        if (!full_perm && !from_library && item_id.notNull())
+                        // permissions for overrides
+                        // Overrides do not permit no-copy textures
+                        LLGLTFMaterial* override = tep->getGLTFMaterialOverride();
+                        if (override != nullptr)
                         {
-                            LLViewerInventoryItem* itemp = gInventory.getItem(item_id);
-                            if (itemp)
+                            for (U32 i = 0; i < LLGLTFMaterial::GLTF_TEXTURE_INFO_COUNT; ++i)
                             {
-                                LLPermissions item_permissions = itemp->getPermissions();
-                                if (item_permissions.allowOperationBy(PERM_COPY,
-                                    gAgent.getID(),
-                                    gAgent.getGroupID()))
+                                LLUUID& texture_id = override->mTextureId[i];
+                                if (texture_id.notNull())
                                 {
-                                    te_data["te"]["imageitemid"] = item_id;
-                                    te_data["te"]["itemfullperm"] = itemp->getIsFullPerm();
-                                    if (!itemp->isFinished())
-                                    {
-                                        // needed for dropTextureAllFaces
-                                        LLInventoryModelBackgroundFetch::instance().start(item_id, false);
-                                    }
+                                    const std::string prefix = "pbr" + std::to_string(i);
+                                    te_data["te"][prefix + "imageid"] = texture_id;
+                                    set_item_availability(texture_id, te_data["te"], prefix, is_creator, asset_item_map, objectp);
                                 }
                             }
                         }
@@ -4201,6 +4248,44 @@ void LLPanelFace::onCopyTexture()
     }
 }
 
+bool get_full_permission(const LLSD& te, const std::string &prefix)
+{
+    return te.has(prefix + "itemfullperm") && te[prefix+"itemfullperm"].asBoolean();
+}
+
+bool LLPanelFace::validateInventoryItem(const LLSD& te, const std::string& prefix)
+{
+    if (te.has(prefix + "itemid"))
+    {
+        LLUUID item_id = te[prefix + "itemid"].asUUID();
+        if (item_id.notNull())
+        {
+            LLViewerInventoryItem* itemp = gInventory.getItem(item_id);
+            if (!itemp)
+            {
+                // image might be in object's inventory, but it can be not up to date
+                LLSD notif_args;
+                static std::string reason = getString("paste_error_inventory_not_found");
+                notif_args["REASON"] = reason;
+                LLNotificationsUtil::add("FacePasteFailed", notif_args);
+                return false;
+            }
+        }
+    }
+    else
+    {
+        // Item was not found on 'copy' stage
+        // Since this happened at copy, might be better to either show this
+        // at copy stage or to drop clipboard here
+        LLSD notif_args;
+        static std::string reason = getString("paste_error_inventory_not_found");
+        notif_args["REASON"] = reason;
+        LLNotificationsUtil::add("FacePasteFailed", notif_args);
+        return false;
+    }
+    return true;
+}
+
 void LLPanelFace::onPasteTexture()
 {
     if (!mClipboardParams.has("texture"))
@@ -4265,39 +4350,49 @@ void LLPanelFace::onPasteTexture()
     for (; iter != end; ++iter)
     {
         const LLSD& te_data = *iter;
-        if (te_data.has("te") && te_data["te"].has("imageid"))
+        if (te_data.has("te"))
         {
-            bool full_perm = te_data["te"].has("itemfullperm") && te_data["te"]["itemfullperm"].asBoolean();
-            full_perm_object &= full_perm;
-            if (!full_perm)
+            if (te_data["te"].has("imageid"))
             {
-                if (te_data["te"].has("imageitemid"))
+                bool full_perm = get_full_permission(te_data["te"], "img");
+                full_perm_object &= full_perm;
+                if (!full_perm)
                 {
-                    LLUUID item_id = te_data["te"]["imageitemid"].asUUID();
-                    if (item_id.notNull())
+                    if (!validateInventoryItem(te_data["te"], "img"))
                     {
-                        LLViewerInventoryItem* itemp = gInventory.getItem(item_id);
-                        if (!itemp)
-                        {
-                            // image might be in object's inventory, but it can be not up to date
-                            LLSD notif_args;
-                            static std::string reason = getString("paste_error_inventory_not_found");
-                            notif_args["REASON"] = reason;
-                            LLNotificationsUtil::add("FacePasteFailed", notif_args);
-                            return;
-                        }
+                        return;
                     }
                 }
-                else
+            }
+            if (te_data["te"].has("pbr"))
+            {
+                bool full_perm = get_full_permission(te_data["te"], "pbr");
+                full_perm_object &= full_perm;
+                if (!full_perm)
                 {
-                    // Item was not found on 'copy' stage
-                    // Since this happened at copy, might be better to either show this
-                    // at copy stage or to drop clipboard here
-                    LLSD notif_args;
-                    static std::string reason = getString("paste_error_inventory_not_found");
-                    notif_args["REASON"] = reason;
-                    LLNotificationsUtil::add("FacePasteFailed", notif_args);
-                    return;
+                    if (!validateInventoryItem(te_data["te"], "pbr"))
+                    {
+                        return;
+                    }
+                }
+                if (te_data["te"].has("pbr_override"))
+                {
+                    for (U32 i = 0; i < LLGLTFMaterial::GLTF_TEXTURE_INFO_COUNT; ++i)
+                    {
+                        const std::string prefix = "pbr" + std::to_string(i);
+                        if (te_data["te"].has(prefix + "imageid"))
+                        {
+                            bool full_perm = get_full_permission(te_data["te"], prefix);
+                            full_perm_object &= full_perm;
+                            if (!full_perm)
+                            {
+                                if (!validateInventoryItem(te_data["te"], prefix))
+                                {
+                                    return;
+                                }
+                            }
+                        }
+                    }
                 }
             }
         }
@@ -4322,6 +4417,71 @@ void LLPanelFace::onPasteTexture()
     selected_objects->applyToTEs(&navigate_home_func);
 }
 
+void get_item_and_permissions(const LLUUID &id, LLViewerInventoryItem*& itemp, bool& full_perm, bool& from_library, const LLSD &data, const std::string &prefix)
+{
+    full_perm = get_full_permission(data, prefix);
+    from_library = data.has(prefix + "fromlibrary") && data.get(prefix + "fromlibrary").asBoolean();
+    LLViewerInventoryItem* itemp_res = NULL;
+
+    if (data.has(prefix + "itemid"))
+    {
+        LLUUID item_id = data.get(prefix + "itemid").asUUID();
+        if (item_id.notNull())
+        {
+            LLViewerInventoryItem* itemp = gInventory.getItem(item_id);
+            if (itemp && itemp->isFinished())
+            {
+                // dropTextureAllFaces will fail if incomplete
+                itemp_res = itemp;
+            }
+            else
+            {
+                // Theoretically shouldn't happend, but if it does happen, we
+                // might need to add a notification to user that paste will fail
+                // since inventory isn't fully loaded
+                LL_WARNS() << "Item " << item_id << " is incomplete, paste might fail silently." << LL_ENDL;
+            }
+        }
+    }
+
+    // for case when item got removed from inventory after we pressed 'copy'
+    // or texture got pasted into previous object
+    if (!itemp_res && !full_perm)
+    {
+        // Due to checks for imageitemid in LLPanelFace::onPasteTexture() this should no longer be reachable.
+        LL_INFOS() << "Item " << data.get(prefix + "itemid").asUUID() << " no longer in inventory." << LL_ENDL;
+        // Todo: fix this, we are often searching same texture multiple times (equal to number of faces)
+        // Perhaps just mPanelFace->onPasteTexture(objectp, te, &asset_to_item_id_map); ? Not pretty, but will work
+        LLViewerInventoryCategory::cat_array_t cats;
+        LLViewerInventoryItem::item_array_t items;
+        LLAssetIDMatches asset_id_matches(id);
+        gInventory.collectDescendentsIf(LLUUID::null,
+            cats,
+            items,
+            LLInventoryModel::INCLUDE_TRASH,
+            asset_id_matches);
+
+        // Extremely unreliable and perfomance unfriendly.
+        // But we need this to check permissions and it is how texture control finds items
+        for (S32 i = 0; i < items.size(); i++)
+        {
+            LLViewerInventoryItem* itemp = items[i];
+            if (itemp && itemp->isFinished())
+            {
+                // dropTextureAllFaces will fail if incomplete
+                LLPermissions item_permissions = itemp->getPermissions();
+                if (item_permissions.allowOperationBy(PERM_COPY,
+                    gAgent.getID(),
+                    gAgent.getGroupID()))
+                {
+                    itemp_res = itemp;
+                    break; // first match
+                }
+            }
+        }
+    }
+}
+
 void LLPanelFace::onPasteTexture(LLViewerObject* objectp, S32 te)
 {
     LLSD te_data;
@@ -4345,77 +4505,22 @@ void LLPanelFace::onPasteTexture(LLViewerObject* objectp, S32 te)
         if (te_data.has("te"))
         {
             // Texture
-            bool full_perm = te_data["te"].has("itemfullperm") && te_data["te"]["itemfullperm"].asBoolean();
-            bool from_library = te_data["te"].has("fromlibrary") && te_data["te"]["fromlibrary"].asBoolean();
             if (te_data["te"].has("imageid"))
             {
+                bool img_full_perm = false;
+                bool img_from_library = false;
                 const LLUUID& imageid = te_data["te"]["imageid"].asUUID(); //texture or asset id
-                LLViewerInventoryItem* itemp_res = NULL;
+                LLViewerInventoryItem* img_itemp_res = NULL;
 
-                if (te_data["te"].has("imageitemid"))
-                {
-                    LLUUID item_id = te_data["te"]["imageitemid"].asUUID();
-                    if (item_id.notNull())
-                    {
-                        LLViewerInventoryItem* itemp = gInventory.getItem(item_id);
-                        if (itemp && itemp->isFinished())
-                        {
-                            // dropTextureAllFaces will fail if incomplete
-                            itemp_res = itemp;
-                        }
-                        else
-                        {
-                            // Theoretically shouldn't happend, but if it does happen, we
-                            // might need to add a notification to user that paste will fail
-                            // since inventory isn't fully loaded
-                            LL_WARNS() << "Item " << item_id << " is incomplete, paste might fail silently." << LL_ENDL;
-                        }
-                    }
-                }
-                // for case when item got removed from inventory after we pressed 'copy'
-                // or texture got pasted into previous object
-                if (!itemp_res && !full_perm)
-                {
-                    // Due to checks for imageitemid in LLPanelFace::onPasteTexture() this should no longer be reachable.
-                    LL_INFOS() << "Item " << te_data["te"]["imageitemid"].asUUID() << " no longer in inventory." << LL_ENDL;
-                    // Todo: fix this, we are often searching same texture multiple times (equal to number of faces)
-                    // Perhaps just mPanelFace->onPasteTexture(objectp, te, &asset_to_item_id_map); ? Not pretty, but will work
-                    LLViewerInventoryCategory::cat_array_t cats;
-                    LLViewerInventoryItem::item_array_t items;
-                    LLAssetIDMatches asset_id_matches(imageid);
-                    gInventory.collectDescendentsIf(LLUUID::null,
-                        cats,
-                        items,
-                        LLInventoryModel::INCLUDE_TRASH,
-                        asset_id_matches);
-
-                    // Extremely unreliable and perfomance unfriendly.
-                    // But we need this to check permissions and it is how texture control finds items
-                    for (S32 i = 0; i < items.size(); i++)
-                    {
-                        LLViewerInventoryItem* itemp = items[i];
-                        if (itemp && itemp->isFinished())
-                        {
-                            // dropTextureAllFaces will fail if incomplete
-                            LLPermissions item_permissions = itemp->getPermissions();
-                            if (item_permissions.allowOperationBy(PERM_COPY,
-                                gAgent.getID(),
-                                gAgent.getGroupID()))
-                            {
-                                itemp_res = itemp;
-                                break; // first match
-                            }
-                        }
-                    }
-                }
+                get_item_and_permissions(imageid, img_itemp_res, img_full_perm, img_from_library, te_data["te"], "img");
 
-                if (itemp_res)
+                if (img_itemp_res)
                 {
                     if (te == -1) // all faces
                     {
                         LLToolDragAndDrop::dropTextureAllFaces(objectp,
-                            itemp_res,
-                            from_library ? LLToolDragAndDrop::SOURCE_LIBRARY : LLToolDragAndDrop::SOURCE_AGENT,
+                            img_itemp_res,
+                            img_from_library ? LLToolDragAndDrop::SOURCE_LIBRARY : LLToolDragAndDrop::SOURCE_AGENT,
                             LLUUID::null,
                             false);
                     }
@@ -4423,15 +4528,15 @@ void LLPanelFace::onPasteTexture(LLViewerObject* objectp, S32 te)
                     {
                         LLToolDragAndDrop::dropTextureOneFace(objectp,
                             te,
-                            itemp_res,
-                            from_library ? LLToolDragAndDrop::SOURCE_LIBRARY : LLToolDragAndDrop::SOURCE_AGENT,
+                            img_itemp_res,
+                            img_from_library ? LLToolDragAndDrop::SOURCE_LIBRARY : LLToolDragAndDrop::SOURCE_AGENT,
                             LLUUID::null,
                             false,
                             0);
                     }
                 }
                 // not an inventory item or no complete items
-                else if (full_perm)
+                else if (img_full_perm)
                 {
                     // Either library, local or existed as fullperm when user made a copy
                     LLViewerTexture* image = LLViewerTextureManager::getFetchedTexture(imageid, FTT_DEFAULT, true, LLGLTexture::BOOST_NONE, LLViewerTexture::LOD_TEXTURE);
@@ -4459,17 +4564,65 @@ void LLPanelFace::onPasteTexture(LLViewerObject* objectp, S32 te)
             // PBR/GLTF
             if (te_data["te"].has("pbr"))
             {
-                objectp->setRenderMaterialID(te, te_data["te"]["pbr"].asUUID(), false /*managing our own update*/);
-                tep->setGLTFRenderMaterial(nullptr);
-                tep->setGLTFMaterialOverride(nullptr);
+                const LLUUID pbr_id = te_data["te"]["pbr"].asUUID();
+                bool pbr_full_perm = false;
+                bool pbr_from_library = false;
+                LLViewerInventoryItem* pbr_itemp_res = NULL;
+
+                get_item_and_permissions(pbr_id, pbr_itemp_res, pbr_full_perm, pbr_from_library, te_data["te"], "pbr");
 
+                bool allow = true;
+
+                // check overrides first since they don't need t be moved to inventory
                 if (te_data["te"].has("pbr_override"))
                 {
-                    LLGLTFMaterialList::queueApply(objectp, te, te_data["te"]["pbr"].asUUID(), te_data["te"]["pbr_override"]);
+                    for (U32 i = 0; i < LLGLTFMaterial::GLTF_TEXTURE_INFO_COUNT; ++i)
+                    {
+                        const std::string prefix = "pbr" + std::to_string(i);
+                        if (te_data["te"].has(prefix + "imageid"))
+                        {
+                            LLUUID tex_id = te_data["te"][prefix + "imageid"];
+
+                            bool full_perm = false;
+                            bool from_library = false;
+                            LLViewerInventoryItem* itemp_res = NULL;
+                            get_item_and_permissions(tex_id, itemp_res, full_perm, from_library, te_data["te"], prefix);
+                            allow = full_perm;
+                            if (!allow) break;
+                        }
+                    }
                 }
-                else
+
+                if (allow && pbr_itemp_res)
+                {
+                    if (pbr_itemp_res)
+                    {
+                        allow = LLToolDragAndDrop::handleDropMaterialProtections(
+                            objectp,
+                            pbr_itemp_res,
+                            pbr_from_library ? LLToolDragAndDrop::SOURCE_LIBRARY : LLToolDragAndDrop::SOURCE_AGENT,
+                            pbr_id);
+                    }
+                    else
+                    {
+                        allow = pbr_full_perm;
+                    }
+                }
+
+                if (allow)
                 {
-                    LLGLTFMaterialList::queueApply(objectp, te, te_data["te"]["pbr"].asUUID());
+                    objectp->setRenderMaterialID(te, te_data["te"]["pbr"].asUUID(), false /*managing our own update*/);
+                    tep->setGLTFRenderMaterial(nullptr);
+                    tep->setGLTFMaterialOverride(nullptr);
+
+                    if (te_data["te"].has("pbr_override"))
+                    {
+                        LLGLTFMaterialList::queueApply(objectp, te, te_data["te"]["pbr"].asUUID(), te_data["te"]["pbr_override"]);
+                    }
+                    else
+                    {
+                        LLGLTFMaterialList::queueApply(objectp, te, te_data["te"]["pbr"].asUUID());
+                    }
                 }
             }
             else
diff --git a/indra/newview/llpanelface.h b/indra/newview/llpanelface.h
index 1ee9bf2cf7..ce3dd8bdea 100644
--- a/indra/newview/llpanelface.h
+++ b/indra/newview/llpanelface.h
@@ -264,6 +264,9 @@ public: // needs to be accessible to selection manager
     void onCopyTexture();
     void onPasteTexture();
     void onPasteTexture(LLViewerObject* objectp, S32 te);
+private:
+    // for copy/paste operations
+    bool validateInventoryItem(const LLSD& te, const std::string& prefix);
 
 protected:
     void menuDoToSelected(const LLSD& userdata);
diff --git a/indra/newview/llpanelprofile.cpp b/indra/newview/llpanelprofile.cpp
index 132098ba99..1fa1c9587f 100644
--- a/indra/newview/llpanelprofile.cpp
+++ b/indra/newview/llpanelprofile.cpp
@@ -328,7 +328,7 @@ public:
         }
 
         const std::string verb = params[1].asString();
-        if (verb == "about")
+        if (verb == "about" || verb == "mention")
         {
             LLAvatarActions::showProfile(avatar_id);
             return true;
diff --git a/indra/newview/llstartup.cpp b/indra/newview/llstartup.cpp
index 9a26ebc5f9..72295ffba9 100644
--- a/indra/newview/llstartup.cpp
+++ b/indra/newview/llstartup.cpp
@@ -3601,7 +3601,7 @@ bool process_login_success_response()
 
     // Agent id needed for parcel info request in LLUrlEntryParcel
     // to resolve parcel name.
-    LLUrlEntryParcel::setAgentID(gAgentID);
+    LLUrlEntryBase::setAgentID(gAgentID);
 
     text = response["session_id"].asString();
     if(!text.empty()) gAgentSessionID.set(text);
diff --git a/indra/newview/llsurfacepatch.cpp b/indra/newview/llsurfacepatch.cpp
index 6f99da5957..875af76c10 100644
--- a/indra/newview/llsurfacepatch.cpp
+++ b/indra/newview/llsurfacepatch.cpp
@@ -210,7 +210,6 @@ void LLSurfacePatch::eval(const U32 x, const U32 y, const U32 stride, LLVector3
     llassert_always(vertex && normal && tex1);
 
     U32 surface_stride = mSurfacep->getGridsPerEdge();
-    U32 texture_stride = mSurfacep->getGridsPerEdge() - 1;
     U32 point_offset = x + y*surface_stride;
 
     *normal = getNormal(x, y);
@@ -223,7 +222,7 @@ void LLSurfacePatch::eval(const U32 x, const U32 y, const U32 stride, LLVector3
 
     // tex0 is used for ownership overlay
     LLVector3 rel_pos = pos_agent - mSurfacep->getOriginAgent();
-    LLVector3 tex_pos = rel_pos * (1.f / (texture_stride * mSurfacep->getMetersPerGrid()));
+    LLVector3 tex_pos = rel_pos * (1.f / (surface_stride * mSurfacep->getMetersPerGrid()));
     tex0->mV[0] = tex_pos.mV[0];
     tex0->mV[1] = tex_pos.mV[1];
 
diff --git a/indra/newview/lltexturectrl.cpp b/indra/newview/lltexturectrl.cpp
index 35057a910a..20127f5f27 100644
--- a/indra/newview/lltexturectrl.cpp
+++ b/indra/newview/lltexturectrl.cpp
@@ -88,7 +88,8 @@ bool get_is_predefined_texture(LLUUID asset_id)
         || asset_id == DEFAULT_OBJECT_NORMAL
         || asset_id == BLANK_OBJECT_NORMAL
         || asset_id == IMG_WHITE
-        || asset_id == LLUUID(SCULPT_DEFAULT_TEXTURE))
+        || asset_id == LLUUID(SCULPT_DEFAULT_TEXTURE)
+        || asset_id == BLANK_MATERIAL_ASSET_ID)
     {
         return true;
     }
diff --git a/indra/newview/llviewerchat.cpp b/indra/newview/llviewerchat.cpp
index 8b01c4ef88..2ca2c5c07d 100644
--- a/indra/newview/llviewerchat.cpp
+++ b/indra/newview/llviewerchat.cpp
@@ -36,6 +36,7 @@
 #include "llviewerregion.h"
 #include "llworld.h"
 #include "llinstantmessage.h" //SYSTEM_FROM
+#include "llurlregistry.h"
 
 // LLViewerChat
 LLViewerChat::font_change_signal_t LLViewerChat::sChatFontChangedSignal;
@@ -222,6 +223,13 @@ void LLViewerChat::formatChatMsg(const LLChat& chat, std::string& formated_msg)
 {
     std::string tmpmsg = chat.mText;
 
+    // show @name instead of slurl for chat mentions
+    LLUrlMatch match;
+    while (LLUrlRegistry::instance().findUrl(tmpmsg, match, LLUrlRegistryNullCallback, false, true))
+    {
+        tmpmsg.replace(match.getStart(), match.getEnd() - match.getStart() + 1, match.getLabel());
+    }
+
     if(chat.mChatStyle == CHAT_STYLE_IRC)
     {
         formated_msg = chat.mFromName + tmpmsg.substr(3);
diff --git a/indra/newview/llviewerfloaterreg.cpp b/indra/newview/llviewerfloaterreg.cpp
index 7d138dfb3b..39c5b9f218 100644
--- a/indra/newview/llviewerfloaterreg.cpp
+++ b/indra/newview/llviewerfloaterreg.cpp
@@ -58,6 +58,7 @@
 #include "llfloatercamera.h"
 #include "llfloatercamerapresets.h"
 #include "llfloaterchangeitemthumbnail.h"
+#include "llfloaterchatmentionpicker.h"
 #include "llfloaterchatvoicevolume.h"
 #include "llfloaterclassified.h"
 #include "llfloaterconversationlog.h"
@@ -356,6 +357,7 @@ void LLViewerFloaterReg::registerFloaters()
     LLFloaterReg::add("chat_voice", "floater_voice_chat_volume.xml", (LLFloaterBuildFunc)&LLFloaterReg::build<LLFloaterChatVoiceVolume>);
     LLFloaterReg::add("change_item_thumbnail", "floater_change_item_thumbnail.xml", (LLFloaterBuildFunc)&LLFloaterReg::build<LLFloaterChangeItemThumbnail>);
     LLFloaterReg::add("nearby_chat", "floater_im_session.xml", (LLFloaterBuildFunc)&LLFloaterIMNearbyChat::buildFloater);
+    LLFloaterReg::add("chat_mention_picker", "floater_chat_mention_picker.xml", (LLFloaterBuildFunc)&LLFloaterReg::build<LLFloaterChatMentionPicker>);
     LLFloaterReg::add("classified", "floater_classified.xml", (LLFloaterBuildFunc)&LLFloaterReg::build<LLFloaterClassified>);
     LLFloaterReg::add("compile_queue", "floater_script_queue.xml", (LLFloaterBuildFunc)&LLFloaterReg::build<LLFloaterCompileQueue>);
     LLFloaterReg::add("conversation", "floater_conversation_log.xml", (LLFloaterBuildFunc)&LLFloaterReg::build<LLFloaterConversationLog>);
diff --git a/indra/newview/llvoavatar.cpp b/indra/newview/llvoavatar.cpp
index 3a52908b8a..a6d50af025 100644
--- a/indra/newview/llvoavatar.cpp
+++ b/indra/newview/llvoavatar.cpp
@@ -6418,6 +6418,16 @@ LLJoint *LLVOAvatar::getJoint( S32 joint_num )
     return pJoint;
 }
 
+void LLVOAvatar::initAllJoints()
+{
+    getJointAliases();
+    for (auto& alias : mJointAliasMap)
+    {
+        mJointMap[alias.first] = mRoot->findJoint(alias.second);
+    }
+    // ignore mScreen and mRoot
+}
+
 //-----------------------------------------------------------------------------
 // getRiggedMeshID
 //
diff --git a/indra/newview/llvoavatar.h b/indra/newview/llvoavatar.h
index a2232d21a2..ab27c5752d 100644
--- a/indra/newview/llvoavatar.h
+++ b/indra/newview/llvoavatar.h
@@ -204,6 +204,7 @@ public:
 
     virtual LLJoint*        getJoint(const std::string &name);
     LLJoint*                getJoint(S32 num);
+    void                    initAllJoints();
 
     //if you KNOW joint_num is a valid animated joint index, use getSkeletonJoint for efficiency
     inline LLJoint* getSkeletonJoint(S32 joint_num) { return mSkeleton[joint_num]; }
diff --git a/indra/newview/llvoavatarself.cpp b/indra/newview/llvoavatarself.cpp
index f23af5afa4..90ff4067f2 100644
--- a/indra/newview/llvoavatarself.cpp
+++ b/indra/newview/llvoavatarself.cpp
@@ -225,6 +225,8 @@ void LLVOAvatarSelf::initInstance()
     doPeriodically(update_avatar_rez_metrics, 5.0);
     doPeriodically(boost::bind(&LLVOAvatarSelf::checkStuckAppearance, this), 30.0);
 
+    initAllJoints(); // mesh thread uses LLVOAvatarSelf as a joint source
+
     mInitFlags |= 1<<2;
 }
 
diff --git a/indra/newview/llvovolume.cpp b/indra/newview/llvovolume.cpp
index 3fb7a3c156..6b3dccf89c 100644
--- a/indra/newview/llvovolume.cpp
+++ b/indra/newview/llvovolume.cpp
@@ -860,8 +860,11 @@ void LLVOVolume::updateTextureVirtualSize(bool forced)
                 // animated faces get moved to a smaller partition to reduce
                 // side-effects of their updates (see shrinkWrap in
                 // LLVOVolume::animateTextures).
-                mDrawable->getSpatialGroup()->dirtyGeom();
-                gPipeline.markRebuild(mDrawable->getSpatialGroup());
+                if (mDrawable->getSpatialGroup())
+                {
+                    mDrawable->getSpatialGroup()->dirtyGeom();
+                    gPipeline.markRebuild(mDrawable->getSpatialGroup());
+                }
             }
         }
 
diff --git a/indra/newview/skins/default/colors.xml b/indra/newview/skins/default/colors.xml
index bc9aef8974..c549a7dddb 100644
--- a/indra/newview/skins/default/colors.xml
+++ b/indra/newview/skins/default/colors.xml
@@ -1004,4 +1004,10 @@
   <color
     name="OutfitSnapshotMacMask2"
     value="0.1 0.1 0.1 1"/>
+  <color
+    name="ChatMentionHighlight"
+    value="0.82 0.91 0.98 0.15" />
+  <color
+    name="ChatSelfMentionHighlight"
+    value="0.85 0.75 0.40 0.5" />
 </colors>
diff --git a/indra/newview/skins/default/xui/en/floater_chat_mention_picker.xml b/indra/newview/skins/default/xui/en/floater_chat_mention_picker.xml
new file mode 100644
index 0000000000..bbad99f932
--- /dev/null
+++ b/indra/newview/skins/default/xui/en/floater_chat_mention_picker.xml
@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
+<floater
+    name="chat_mention_picker"
+    title="CHOOSE RESIDENT"
+    single_instance="true"
+    can_minimize="false"
+    can_tear_off="false"
+    can_resize="true"
+    auto_close="true"
+    layout="topleft"
+    min_width="250"
+    chrome="true"
+    height="125"
+    width="310">
+   <avatar_list
+    allow_select="true"
+    follows="all"
+    height="120"
+    width="306"
+    ignore_online_status="true"
+    layout="topleft"
+    left="3"
+    keep_one_selected="true"
+    multi_select="false"
+    show_info_btn="false"
+    show_profile_btn="false"
+    show_speaking_indicator="false"
+    name="avatar_list"
+    right="-1"
+    top="2" />
+</floater>
diff --git a/indra/newview/skins/default/xui/en/panel_tools_texture.xml b/indra/newview/skins/default/xui/en/panel_tools_texture.xml
index af6a9b94d9..b7db9dec96 100644
--- a/indra/newview/skins/default/xui/en/panel_tools_texture.xml
+++ b/indra/newview/skins/default/xui/en/panel_tools_texture.xml
@@ -968,8 +968,8 @@
              label_width="205"
              layout="topleft"
              left="10"
-             min_val="-100"
-             max_val="100"
+             min_val="-10000"
+             max_val="10000"
              name="gltfTextureScaleU"
              top_delta="34"
              width="265" />
@@ -981,8 +981,8 @@
              label_width="205"
              layout="topleft"
              left="10"
-             min_val="-100"
-             max_val="100"
+             min_val="-10000"
+             max_val="10000"
              name="gltfTextureScaleV"
              width="265" />
             <spinner