diff --git a/indra/newview/llimpanel.cpp b/indra/newview/llimpanel.cpp
index af2659486..aaf79dbfc 100644
--- a/indra/newview/llimpanel.cpp
+++ b/indra/newview/llimpanel.cpp
@@ -60,7 +60,7 @@
 #include "llviewerwindow.h"
 #include "llvoicechannel.h"
 
-#include "boost/algorithm/string.hpp"
+#include <boost/lambda/lambda.hpp>
 
 // [RLVa:KB] - Checked: 2013-05-10 (RLVa-1.4.9)
 #include "rlvactions.h"
@@ -321,6 +321,7 @@ LLFloaterIMPanel::LLFloaterIMPanel(
 	case IM_SESSION_GROUP_START:
 	case IM_SESSION_INVITE:
 	case IM_SESSION_CONFERENCE_START:
+		mCommitCallbackRegistrar.add("FlipDing", boost::bind<void>(boost::lambda::_1 = !boost::lambda::_1, boost::ref(mDing)));
 		// determine whether it is group or conference session
 		if (gAgent.isInGroup(mSessionUUID))
 		{
diff --git a/indra/newview/skins/default/xui/en-us/floater_instant_message_ad_hoc.xml b/indra/newview/skins/default/xui/en-us/floater_instant_message_ad_hoc.xml
index 332def37b..54cdff914 100644
--- a/indra/newview/skins/default/xui/en-us/floater_instant_message_ad_hoc.xml
+++ b/indra/newview/skins/default/xui/en-us/floater_instant_message_ad_hoc.xml
@@ -11,7 +11,10 @@
 	<layout_stack border="false" bottom="0" follows="left|top|right|bottom" height="180" left="0" orientation="horizontal" tab_group="1" width="496" name="panels">
 		<layout_panel border="false" bottom="0" default_tab_group="1" follows="left|top|bottom|right" height="195" left="0" min_width="115" name="im_contents_panel" width="495">
 			<button bottom="-20" follows="left|top" height="20" label="History" left="5" name="history_btn" width="80"/>
-			<button bottom_delta="0" enabled="false" follows="left|top" height="20" image_overlay="icn_voice-call-start.tga" image_overlay_alignment="left" label="Call" left_delta="80" name="start_call_btn" width="80"/>
+            <button bottom_delta="0" follows="left|top" height="20" left_delta="80" width="50" toggle="true" name="ding_btn" label="Ding">
+              <button.commit_callback function="FlipDing"/>
+            </button>
+            <button bottom_delta="0" enabled="false" follows="left|top" height="20" image_overlay="icn_voice-call-start.tga" image_overlay_alignment="left" label="Call" left_delta="50" name="start_call_btn" width="80"/>
 			<button bottom_delta="0" follows="left|top" height="20" image_overlay="icn_voice-call-end.tga" image_overlay_alignment="left" label="End Call" left_delta="0" name="end_call_btn" visible="false" width="80"/>
 			<button bottom_delta="0" follows="right|top" height="20" label="&lt; &lt;" label_selected="&gt; &gt;" left="462" name="toggle_active_speakers_btn" right="495" tool_tip="Click here to toggle a list of active participants in this IM session." visible="true" width="80"/>
 			<text_editor bottom="28" type="string" length="1" bg_readonly_color="ChatHistoryBgColor" bg_writeable_color="ChatHistoryBgColor" enabled="false" follows="left|top|right|bottom" font="SansSerif" height="143" left="5" max_length="2147483647" name="im_history" track_bottom="true" text_color="ChatHistoryTextColor" text_readonly_color="ChatHistoryTextColor" width="490" word_wrap="true"/>
diff --git a/indra/newview/skins/default/xui/en-us/floater_instant_message_ad_hoc_concisebuttons.xml b/indra/newview/skins/default/xui/en-us/floater_instant_message_ad_hoc_concisebuttons.xml
index 6a426e664..57188eac1 100644
--- a/indra/newview/skins/default/xui/en-us/floater_instant_message_ad_hoc_concisebuttons.xml
+++ b/indra/newview/skins/default/xui/en-us/floater_instant_message_ad_hoc_concisebuttons.xml
@@ -9,7 +9,10 @@
 	<string name="session_start_string">Starting session with [NAME], please wait.</string>
 	<string name="default_text_label">Click here to instant message.</string>
 	<button bottom="-20" follows="right|top" height="20" label="History" right="-165" name="history_btn" width="80"/>
-	<button bottom_delta="0" enabled="false" follows="right|top" height="20" image_overlay="icn_voice-call-start.tga" image_overlay_alignment="left" label="Call" left_delta="80" name="start_call_btn" width="80"/>
+    <button bottom_delta="0" follows="left|top" height="20" left_delta="80" width="50" toggle="true" name="ding_btn" label="Ding">
+      <button.commit_callback function="FlipDing"/>
+    </button>
+    <button bottom_delta="0" enabled="false" follows="right|top" height="20" image_overlay="icn_voice-call-start.tga" image_overlay_alignment="left" label="Call" left_delta="50" name="start_call_btn" width="80"/>
 	<button bottom_delta="0" follows="right|top" height="20" image_overlay="icn_voice-call-end.tga" image_overlay_alignment="left" label="End Call" left_delta="0" name="end_call_btn" visible="false" width="80"/>
 	<button bottom_delta="0" follows="right|top" height="20" label="&lt; &lt;" label_selected="&gt; &gt;" left="420" name="toggle_active_speakers_btn" right="450" tool_tip="Click here to toggle a list of active participants in this IM session." visible="true" width="80"/>
 	<layout_stack border="false" bottom="0" follows="left|top|right|bottom" height="180" left="0" orientation="horizontal" tab_group="1" width="496" name="panels">
diff --git a/indra/newview/skins/default/xui/en-us/floater_instant_message_group.xml b/indra/newview/skins/default/xui/en-us/floater_instant_message_group.xml
index 4bea6a419..03c8ce016 100644
--- a/indra/newview/skins/default/xui/en-us/floater_instant_message_group.xml
+++ b/indra/newview/skins/default/xui/en-us/floater_instant_message_group.xml
@@ -14,7 +14,10 @@
 		<layout_panel border="false" bottom="0" default_tab_group="1" follows="left|top|bottom|right" height="195" left="0" min_width="210" name="im_contents_panel" width="495">
 			<button bottom="-20" follows="left|top" height="20" label="Group Info" left="5" name="group_info_btn" tab_group="0" width="80"/>
 			<button bottom_delta="0" follows="left|top" height="20" label="History" left_delta="80" name="history_btn" width="80"/>
-			<button bottom_delta="0" enabled="false" follows="left|top" halign="right" height="20" image_overlay="icn_voice-call-start.tga" image_overlay_alignment="left" label="Join Call" left_delta="80" name="start_call_btn" width="80"/>
+            <button bottom_delta="0" follows="left|top" height="20" left_delta="80" width="50" toggle="true" name="ding_btn" label="Ding">
+              <button.commit_callback function="FlipDing"/>
+            </button>
+            <button bottom_delta="0" enabled="false" follows="left|top" halign="right" height="20" image_overlay="icn_voice-call-start.tga" image_overlay_alignment="left" label="Join Call" left_delta="50" name="start_call_btn" width="80"/>
 			<button bottom_delta="0" follows="left|top" halign="right" height="20" image_overlay="icn_voice-call-end.tga" image_overlay_alignment="left" label="End Call" left_delta="0" name="end_call_btn" pad_right="12" visible="false" width="80"/>
 			<button bottom_delta="0" follows="right|top" height="20" label="&lt; &lt;" label_selected="&gt; &gt;" left="462" name="toggle_active_speakers_btn" right="495" tool_tip="Click here to toggle a list of active participants in this IM session." visible="true" width="80"/>
 			<text_editor bottom="28" type="string" length="1" bg_readonly_color="ChatHistoryBgColor" bg_writeable_color="ChatHistoryBgColor" enabled="false" follows="left|top|right|bottom" font="SansSerif" height="143" left="5" max_length="2147483647" name="im_history" track_bottom="true" text_color="ChatHistoryTextColor" text_readonly_color="ChatHistoryTextColor" width="490" word_wrap="true"/>
diff --git a/indra/newview/skins/default/xui/en-us/floater_instant_message_group_concisebuttons.xml b/indra/newview/skins/default/xui/en-us/floater_instant_message_group_concisebuttons.xml
index ffa3e9485..f43c4b311 100644
--- a/indra/newview/skins/default/xui/en-us/floater_instant_message_group_concisebuttons.xml
+++ b/indra/newview/skins/default/xui/en-us/floater_instant_message_group_concisebuttons.xml
@@ -12,7 +12,10 @@
 	<string name="muted_text_label">Your text chat has been disabled by a Group Moderator.</string>
 	<button bottom="-20" follows="right|top" height="20" label="Group Info" right="-245" name="group_info_btn" tab_group="0" width="80"/>
 	<button bottom_delta="0" follows="right|top" height="20" label="History" left_delta="80" name="history_btn" width="80"/>
-	<button bottom_delta="0" enabled="false" follows="right|top" halign="right" height="20" image_overlay="icn_voice-call-start.tga" image_overlay_alignment="left" label="Join Call" left_delta="80" name="start_call_btn" width="80"/>
+    <button bottom_delta="0" follows="left|top" height="20" left_delta="80" width="50" toggle="true" name="ding_btn" label="Ding">
+      <button.commit_callback function="FlipDing"/>
+    </button>
+    <button bottom_delta="0" enabled="false" follows="right|top" halign="right" height="20" image_overlay="icn_voice-call-start.tga" image_overlay_alignment="left" label="Join Call" left_delta="50" name="start_call_btn" width="80"/>
 	<button bottom_delta="0" follows="right|top" halign="right" height="20" image_overlay="icn_voice-call-end.tga" image_overlay_alignment="left" label="End Call" left_delta="0" name="end_call_btn" pad_right="12" visible="false" width="80"/>
 	<button bottom_delta="0" follows="right|top" height="20" label="&lt; &lt;" label_selected="&gt; &gt;" left="420" name="toggle_active_speakers_btn" right="450" tool_tip="Click here to toggle a list of active participants in this IM session." visible="true" width="80"/>
 	<layout_stack border="false" bottom="0" follows="left|top|right|bottom" height="180" left="0" orientation="horizontal" tab_group="1" width="496" name="panels">