diff --git a/mozilla/mail/app/profile/mailnews.js b/mozilla/mail/app/profile/mailnews.js
index cadf6850d79..1d390b43b5d 100644
--- a/mozilla/mail/app/profile/mailnews.js
+++ b/mozilla/mail/app/profile/mailnews.js
@@ -128,6 +128,7 @@ pref("mail.strictly_mime_headers",          true);
 pref("mail.file_attach_binary",             false);
 pref("mail.show_headers",                   1); // some
 pref("mail.pane_config",                    0);
+pref("mail.pane_config.dynamic",            0); // new pref used for dynamic pane configuration
 pref("mail.addr_book.mapit_url.format", "chrome://messenger-region/locale/region.properties");
 
 // the format for "mail.addr_book.quicksearchquery.format" is:
@@ -290,12 +291,6 @@ pref("mailnews.start_page.enabled", true);
 
 pref("mailnews.remember_selected_message", true);
 
-pref("mail.toolbars.showbutton.file", true);
-pref("mail.toolbars.showbutton.next", true);
-pref("mail.toolbars.showbutton.junk", true);
-pref("mail.toolbars.showbutton.print", true);
-pref("mail.toolbars.showbutton.stop", true);
-
 pref("mailnews.account_central_page.url", "chrome://messenger/locale/messenger.properties");
 
 /* default prefs for Mozilla 5.0 */
diff --git a/mozilla/mail/base/content/aboutDialog.xul b/mozilla/mail/base/content/aboutDialog.xul
index b4bfc66952e..4185abbdc33 100644
--- a/mozilla/mail/base/content/aboutDialog.xul
+++ b/mozilla/mail/base/content/aboutDialog.xul
@@ -47,6 +47,7 @@
 
 <dialog xmlns:html="http://www.w3.org/1999/xhtml"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        id="aboutdlg"
         buttons="accept"
         onload="onLoad();"
         title="&aboutDialog.title;"
@@ -56,7 +57,10 @@
       <![CDATA[
         function onLoad() {
           var versionField = document.getElementById("versionField");
-          versionField.value = navigator.vendorSub + ' (' + navigator.productSub + ')';
+          var brandShortNameEl = document.getElementById("brandShortName");          
+          versionField.value = brandShortNameEl.firstChild.nodeValue + ' ' + navigator.vendorSub + ' (' + navigator.productSub + ')';
+          versionField.size = versionField.value.length - 5; // total hack..we are calculating a length that is too long, 
+                                                             // which keeps the text box from looking centered in the dialog.
         }
       ]]>
     </script>
diff --git a/mozilla/mail/base/content/commandglue.js b/mozilla/mail/base/content/commandglue.js
index 2fd9b85085d..5965959b9e7 100644
--- a/mozilla/mail/base/content/commandglue.js
+++ b/mozilla/mail/base/content/commandglue.js
@@ -621,7 +621,7 @@ function CreateDBView(msgFolder, viewType, viewFlags, sortType, sortOrder)
 
   // based on the collapsed state of the thread pane/message pane splitter,
   // suppress message display if appropriate.
-  gDBView.suppressMsgDisplay = IsThreadAndMessagePaneSplitterCollapsed();
+  gDBView.suppressMsgDisplay = IsMessagePaneCollapsed();
 
   UpdateSortIndicators(gCurSortType, sortOrder);
 }
@@ -658,8 +658,13 @@ function GetSelectedFolderResource()
     return GetFolderResource(folderTree, startIndex.value);
 }
 
-function NotifyChangedMessagePaneVisibility(now_hidden)
+function ChangeMessagePaneVisibility(now_hidden)
 {
+  if (gDBView) {
+    // the collapsed state is the state after we released the mouse 
+    // so we take it as it is
+    gDBView.suppressMsgDisplay = now_hidden;
+  }
   var event = document.createEvent('Events');
   if (now_hidden) {
     event.initEvent('messagepane-hide', false, true);
@@ -674,11 +679,7 @@ function OnMouseUpThreadAndMessagePaneSplitter()
 {
   // the collapsed state is the state after we released the mouse 
   // so we take it as it is
-  var now_hidden = IsThreadAndMessagePaneSplitterCollapsed();
-  if (gDBView) {
-    gDBView.suppressMsgDisplay = now_hidden;
-  }
-  NotifyChangedMessagePaneVisibility(now_hidden);
+  ChangeMessagePaneVisibility(IsMessagePaneCollapsed());
 }
 
 function FolderPaneSelectionChange()
diff --git a/mozilla/mail/base/content/mailTasksOverlay.xul b/mozilla/mail/base/content/mailTasksOverlay.xul
index c27c0ae3431..06cd42a1647 100644
--- a/mozilla/mail/base/content/mailTasksOverlay.xul
+++ b/mozilla/mail/base/content/mailTasksOverlay.xul
@@ -14,19 +14,7 @@
     // which is included by most clients. 
     function toMessengerWindow()
       {
-        var pref = Components.classes["@mozilla.org/preferences-service;1"]
-                             .getService(Components.interfaces.nsIPrefBranch);
-        var windowDoc = "chrome://messenger/content/messenger.xul";
-        try
-          {
-            var layoutType = pref.getIntPref("mail.pane_config");
-            windowDoc = !layoutType ? "chrome://messenger/content/messenger.xul" : 
-                                          "chrome://messenger/content/mail3PaneWindowVertLayout.xul";
-          }
-        catch(ex)
-          {
-          }
-        toOpenWindowByType("mail:3pane", windowDoc);
+        toOpenWindowByType("mail:3pane", "chrome://messenger/content/");
       }
     
     function toAddressBook() 
diff --git a/mozilla/mail/base/content/mailWindow.js b/mozilla/mail/base/content/mailWindow.js
index 517f5a0fe58..076085b0e92 100644
--- a/mozilla/mail/base/content/mailWindow.js
+++ b/mozilla/mail/base/content/mailWindow.js
@@ -58,12 +58,8 @@ var folderDataSource;
 
 var accountCentralBox = null;
 var gSearchBox = null;
-var gThreadPane = null;
-var gThreadPaneSplitter = null;
-var gMessagePaneBox = null;
 var gAccountCentralLoaded = false;
 var gFakeAccountPageLoaded = false;
-var gPaneConfig = null;
 //End progress and Status variables
 
 // for checking if the folder loaded is Draft or Unsent which msg is editable
@@ -188,10 +184,6 @@ function CreateMailWindowGlobals()
 
   accountCentralBox = document.getElementById("accountCentralBox");
   gSearchBox = document.getElementById("searchBox");
-  gThreadPane = document.getElementById("threadTree");
-  gThreadPaneSplitter = document.getElementById("threadpane-splitter");
-  gMessagePaneBox = document.getElementById("messagepanebox");
-  gPaneConfig = pref.getIntPref("mail.pane_config");
 }
 
 function InitMsgWindow()
@@ -496,26 +488,19 @@ function loadStartPage() {
 // Load iframe in the AccountCentral box with corresponding page
 function ShowAccountCentral()
 {
-    var acctCentralPage = pref.getComplexValue("mailnews.account_central_page.url",
-                                               Components.interfaces.nsIPrefLocalizedString).data;
-    gSearchBox.setAttribute("collapsed", "true");
-    gThreadPane.setAttribute("collapsed", "true");
-    gMessagePaneBox.setAttribute("collapsed", "true");
-    accountCentralBox.removeAttribute("collapsed");
-    window.frames["accountCentralPane"].location = acctCentralPage;
-    gAccountCentralLoaded = true;
-
     try
     {
-        switch (gPaneConfig)
-        {
-            case 0:
-                break;
-
-            case 1:
-                gThreadPaneSplitter.setAttribute("collapsed", "true");
-                break;
-        }
+    var acctCentralPage = pref.getComplexValue("mailnews.account_central_page.url",
+                                               Components.interfaces.nsIPrefLocalizedString).data;
+        GetMessagePane().collapsed = true;
+        document.getElementById("threadpane-splitter").collapsed = true;
+        gSearchBox.collapsed = true;
+        GetThreadTree().collapsed = true;
+        document.getElementById("accountCentralBox").collapsed = false;
+    window.frames["accountCentralPane"].location = acctCentralPage;
+        if (!IsFolderPaneCollapsed())
+            GetFolderTree().focus();
+    gAccountCentralLoaded = true;
     }
     catch (ex)
     {
@@ -529,24 +514,16 @@ function ShowAccountCentral()
 // box and display message box.
 function HideAccountCentral()
 {
-    gSearchBox.removeAttribute("collapsed");
-    gThreadPane.removeAttribute("collapsed");
-    gMessagePaneBox.removeAttribute("collapsed");
-    accountCentralBox.setAttribute("collapsed", "true");
-    window.frames["accountCentralPane"].location = "about:blank";
-    gAccountCentralLoaded = false;
-
     try
     {
-        switch (gPaneConfig)
-        {
-            case 0:
-                break;
-
-            case 1:
-                gThreadPaneSplitter.removeAttribute("collapsed");
-                break;
-        }
+        window.frames["accountCentralPane"].location = "about:blank";
+        document.getElementById("accountCentralBox").collapsed = true;
+        GetThreadTree().collapsed = false;
+        gSearchBox.collapsed = false;
+        var threadPaneSplitter = document.getElementById("threadpane-splitter");
+        threadPaneSplitter.collapsed = false;
+        GetMessagePane().collapsed = threadPaneSplitter.getAttribute("state") == "collapsed";
+        gAccountCentralLoaded = false;
     }
     catch (ex)
     {
@@ -635,42 +612,3 @@ function SetKeywords(aKeywords)
   // cache the keywords 
   gLastKeywords = aKeywords;
 }
-
-function ShowHideToolBarButtons()
-{
-  return;
-}
-  
-function AddToolBarPrefListener()
-{
-  try {
-    var pbi = pref.QueryInterface(Components.interfaces.nsIPrefBranchInternal);
-    pbi.addObserver(gMailToolBarPrefListener.domain, gMailToolBarPrefListener, false);
-  } catch(ex) {
-    dump("Failed to observe prefs: " + ex + "\n");
-  }
-}
-
-function RemoveToolBarPrefListener()
-{
-  try {
-    var pbi = pref.QueryInterface(Components.interfaces.nsIPrefBranchInternal);
-    pbi.removeObserver(gMailToolBarPrefListener.domain, gMailToolBarPrefListener);
-  } catch(ex) {
-    dump("Failed to remove pref observer: " + ex + "\n");
-  }
-}
-
-// Pref listener constants
-const gMailToolBarPrefListener =
-{
-  domain: "mail.toolbars.showbutton",
-  observe: function(subject, topic, prefName)
-  {
-    // verify that we're changing a button pref
-    if (topic != "nsPref:changed")
-      return;
-
-    document.getElementById("button-" + prefName.substr(this.domain.length+1)).hidden = !(pref.getBoolPref(prefName));
-  }
-};
diff --git a/mozilla/mail/base/content/mailWindowOverlay.js b/mozilla/mail/base/content/mailWindowOverlay.js
index a7431ba9dec..e7dccf02a9e 100644
--- a/mozilla/mail/base/content/mailWindowOverlay.js
+++ b/mozilla/mail/base/content/mailWindowOverlay.js
@@ -169,7 +169,8 @@ function view_init()
   {
       var message_menuitem_hidden = message_menuitem.getAttribute("hidden");
       if(message_menuitem_hidden != "true"){
-          message_menuitem.setAttribute('checked',!IsThreadAndMessagePaneSplitterCollapsed());
+          message_menuitem.setAttribute('checked', !IsMessagePaneCollapsed());
+          message_menuitem.setAttribute('disabled', gAccountCentralLoaded);
       }
   }
 
@@ -1100,12 +1101,8 @@ function MsgOpenNewWindowForFolder(uri, key)
     // will return the message that is highlighted.
     uriToOpen = GetSelectedFolderURI();
 
-  if (uriToOpen) {
-   // get the messenger window open service and ask it to open a new window for us
-   var mailWindowService = Components.classes["@mozilla.org/messenger/windowservice;1"].getService(Components.interfaces.nsIMessengerWindowService);
-   if (mailWindowService)
-     mailWindowService.openMessengerWindowWithUri("mail:3pane", uriToOpen, keyToSelect);
-  }
+  if (uriToOpen)
+    window.openDialog("chrome://messenger/content/", "_blank", "chrome,all,dialog=no", uriToOpen, keyToSelect);
 }
 
 // passing in the view, so this will work for search and the thread pane
diff --git a/mozilla/mail/base/content/messageWindow.js b/mozilla/mail/base/content/messageWindow.js
index 3dd01d62e9a..59903cb1633 100644
--- a/mozilla/mail/base/content/messageWindow.js
+++ b/mozilla/mail/base/content/messageWindow.js
@@ -255,8 +255,6 @@ function delayedOnLoadMessageWindow()
   AddMailOfflineObserver();
 	CreateMailWindowGlobals();
 	CreateMessageWindowGlobals();
-  AddToolBarPrefListener();
-  ShowHideToolBarButtons()
 	verifyAccounts(null);
 
 	InitMsgWindow();
@@ -477,7 +475,6 @@ function HideMenus()
 
 function OnUnloadMessageWindow()
 {
-  RemoveToolBarPrefListener();
 	// FIX ME - later we will be able to use onunload from the overlay
 	OnUnloadMsgHeaderPane();
 
diff --git a/mozilla/mail/base/content/messenger.xul b/mozilla/mail/base/content/messenger.xul
index ba7097ade31..cf19642f7e3 100644
--- a/mozilla/mail/base/content/messenger.xul
+++ b/mozilla/mail/base/content/messenger.xul
@@ -94,7 +94,6 @@
         events="focus"
         oncommandupdate="FocusRingUpdate_Mail()"/>
   <commandset id="tasksCommands"/>
-  <command id="toggleSidebar"/>
 </commandset>
 
 <broadcasterset id="mailBroadcasters">
@@ -104,7 +103,6 @@
 </broadcasterset>
 
 <keyset id="mailKeys">
-  <key id="showHideSidebar"/>
   <keyset id="tasksKeys"/>
 </keyset>
 
@@ -140,14 +138,19 @@
   <toolbox id="mail-toolbox" class="toolbox-top">
   </toolbox>
 
-  <hbox style="height:100px" flex="1">
-    <vbox id="folderPaneBox" flex="1" autostretch="always" persist="width">
+  <!-- when we move to the alternate 3-pane, mailContentWrapper gets toggled to a vertical orientation -->
+  <box id="mailContentWrapper" orient="horizontal" flex="1">
+
+  <hbox id="mailContent" flex="1">
+    
+    <vbox id="folderPaneBox" minwidth="100" width="200" persist="collapsed width">
+    
       <sidebarheader id="folderPaneHeader" align="center">
         <label id="folderpane-title" value="&folderPaneHeader.label;"/>
       </sidebarheader>
-      <tree id="folderTree" class="plain focusring" flex="1" seltype="single" style="min-width: 100px;"
+      
+      <tree id="folderTree" class="plain focusring" flex="1" seltype="single"
             context="folderPaneContext"
-            persist="collapsed width height"
             disableKeyNavigation="true"
             datasources="rdf:null"
             hidecolumnpicker="true"
@@ -237,16 +240,14 @@
       
     <splitter id="gray_vertical_splitter" collapse="before" persist="state"/>
     
-    <vbox id="messengerBox" flex="1" persist="width">
-      <!-- collapse this box.  since we are loading on a timeout, the user will see it "jump" if it isn't collapsed" -->
-      <vbox id="accountCentralBox" flex="1" collapsed="true">
-        <iframe name="accountCentralPane" flex="1" src="about:blank"/>
-      </vbox>
+    <vbox flex="1">
       <hbox id="searchBox"/>
+    
+      <box orient="vertical" id="messagesBox" flex="1">
+        <hbox id="messengerBox" flex="1" minheight="100" height="100" persist="height">
+          <vbox id="threadPaneBox" flex="1">          
         <tree id="threadTree" flex="2" enableColumnDrag="true" _selectDelay="500" class="plain focusring"
                      disableKeyNavigation="true"
-                     persist="height"
-                     style="height:0px" 
                      context="threadPaneContext"
                      onkeypress="ThreadPaneKeyPress(event);"
                      onselect="ThreadPaneSelectionChanged();">
@@ -302,28 +303,32 @@
           </treecols>
         <treechildren ondraggesture="BeginDragThreadPane(event);"/>
       </tree>
+            <vbox id="accountCentralBox" flex="1" collapsed="true">
+              <iframe name="accountCentralPane" width="150" flex="1" src="about:blank"/>
+            </vbox>
+          </vbox>
+        </hbox>
 
       <!-- if you change this id, please change GetThreadAndMessagePaneSplitter() and MsgToggleMessagePane() -->
-      <splitter collapse="after" persist="state" 
-		onmouseup="OnMouseUpThreadAndMessagePaneSplitter()"
-                id="threadpane-splitter"/>
-      
-      <vbox id="messagepanebox" flex="3" persist="collapsed height" onclick="contentAreaClick(event);">
+        <splitter id="threadpane-splitter" collapse="after" persist="state"
+                  onmouseup="OnMouseUpThreadAndMessagePaneSplitter()"/>
 
+        <vbox id="messagepanebox" flex="2" minheight="100" height="200" persist="collapsed height width">
         <hbox id="junkBar"/>
-
         <hbox id="msgHeaderView"/>
-    
-        <browser id="messagepane" context="messagePaneContext"
-                 style="height: 0px; min-height: 1px" flex="1" name="messagepane" 
+          <browser id="messagepane" context="messagePaneContext" autofind="false"
+                   minheight="1" height="0" flex="1" name="messagepane"
                  disablehistory="true" type="content-primary" src="about:blank"
-                 disablesecurity="true" autofind="false"/>
+                   disablesecurity="true" onclick="contentAreaClick(event);"/>
       </vbox>  
+      </box>
     </vbox>             
   </hbox>
 
+  </box> <!-- end of mailContentWrapper -->
+
   <statusbar id="status-bar" class="chromeclass-status mailwindow-statusbar">
-    <statusbarpanel id="unreadMessageCount" style="min-width: 5px"/>
-    <statusbarpanel id="totalMessageCount" style="min-width: 5px"/>
+    <statusbarpanel id="unreadMessageCount"/>
+    <statusbarpanel id="totalMessageCount"/>
   </statusbar>
 </window>
diff --git a/mozilla/mail/base/content/msgMail3PaneWindow.js b/mozilla/mail/base/content/msgMail3PaneWindow.js
index d53042f9e12..702f1387d12 100644
--- a/mozilla/mail/base/content/msgMail3PaneWindow.js
+++ b/mozilla/mail/base/content/msgMail3PaneWindow.js
@@ -30,6 +30,10 @@ const nsMsgKey_None = 0xFFFFFFFF;
 const nsMsgViewIndex_None = 0xFFFFFFFF;
 const kMailCheckOncePrefName = "mail.startup.enabledMailCheckOnce";
 
+const kStandardPaneConfig = 0;
+const kWidePaneConfig = 1;
+const kVerticalPaneConfig = 2;
+
 var gFolderTree; 
 var gMessagePane;
 var gThreadTree;
@@ -38,6 +42,7 @@ var gSearchInput;
 var gThreadAndMessagePaneSplitter = null;
 var gUnreadCount = null;
 var gTotalCount = null;
+var gCurrentPaneConfig = 0;
 
 var gCurrentLoadingFolderURI;
 var gCurrentFolderToReroot;
@@ -616,20 +621,109 @@ var gThreePaneIncomingServerListener = {
     }
 }
 
+// aMsgWindowInitialized: false if we are calling from the onload handler, otherwise true
+
+function UpdateMailPaneConfig(aMsgWindowInitialized) {
+  var paneConfig = pref.getIntPref("mail.pane_config.dynamic");
+  
+  // don't do anything if we are already in the correct configuration
+  if (paneConfig == gCurrentPaneConfig)
+    return;
+
+  var mailContentWrapper = document.getElementById("mailContentWrapper");
+  var messagesBox = document.getElementById("messagesBox");
+  var messagePaneBox = GetMessagePane();
+  var msgPaneReRooted = false;
+
+  var threadPaneSplitter = GetThreadAndMessagePaneSplitter();
+
+  // the only element we need to re-root is the message pane.
+  var desiredMsgPaneParentId = (paneConfig == "0" || paneConfig == "2") ? "messagesBox" : "mailContentWrapper";
+
+  if (messagePaneBox.parentNode.id != desiredMsgPaneParentId)
+  {
+     var messagePaneParent = document.getElementById(messagePaneBox.parentNode.id);
+     messagePaneParent.removeChild(threadPaneSplitter);
+     messagePaneParent.removeChild(messagePaneBox);
+
+     var messagePaneNewParent = document.getElementById(desiredMsgPaneParentId);
+     messagePaneNewParent.appendChild(threadPaneSplitter); 
+     messagePaneNewParent.appendChild(messagePaneBox); 
+     msgPaneReRooted = true;
+  }
+
+  // now for each config, handle any extra clean up to create that view (such as changing a box orientation)
+  if (paneConfig == kStandardPaneConfig) // standard 3-Pane Layout
+  {     
+    messagePaneBox.removeAttribute("minwidth");
+    threadPaneSplitter.setAttribute("orient", "vertical");
+
+    // finally, make sure mailContentWrapper has the correct orientation
+    mailContentWrapper.setAttribute("orient", "horizontal");
+    messagesBox.setAttribute("orient", "vertical");
+  }
+
+  else if (paneConfig == kWidePaneConfig)  // "Wide" Window Pane Layout
+  {  
+    messagePaneBox.removeAttribute("minwidth");   
+    threadPaneSplitter.setAttribute("orient", "vertical");
+
+    // finally, make sure mailContentWrapper has the correct orientation
+    mailContentWrapper.setAttribute("orient", "vertical");
+    messagesBox.setAttribute("orient", "vertical");
+  }
+  
+  else if (paneConfig == kVerticalPaneConfig) // Vertical Pane Layout
+  {
+    messagesBox.setAttribute("orient", "horizontal");
+    threadPaneSplitter.removeAttribute("orient");
+    messagePaneBox.setAttribute("minwidth", "400"); // 400 is a made up number since I can't seem to force the thread pane and msg pane
+                                                    // to split the available space in half (why is flex not working here???)
+    // finally, make sure mailContentWrapper has the correct orientation
+    mailContentWrapper.setAttribute("orient", "horizontal");
+  }
+
+  // re-rooting the message pane causes the docshell to get destroyed 
+  // and replaced with another one. As such, we need to re-set the window (and thus the 
+  // internal references nsMessenger keeps for the message pane docshell)
+  // XXX: is it safe to call this multiple times? May need to add a setMessagePaneDocShell
+  //      routine to nsIMessenger.
+
+  if (aMsgWindowInitialized && msgPaneReRooted)
+  {
+    messenger.SetWindow(null, null);
+    messenger.SetWindow(window, msgWindow);
+    MsgReload(); 
+  }
+  
+  // record the new configuration
+  gCurrentPaneConfig = paneConfig; 
+}
+
+const MailPaneConfigObserver = {
+  observe: function(subject, topic, prefName) {
+    // verify that we're changing the mail pane config pref
+    if (topic == "nsPref:changed")
+      UpdateMailPaneConfig(true);
+  }
+};
 
 function OnLoadMessenger()
 {
+  // update the pane config before we exit onload otherwise the user may see a flicker if we poke the document
+  // in delayedOnLoadMessenger...
+  UpdateMailPaneConfig(false);
+
   setTimeout(delayedOnLoadMessenger, 0); // when debugging, set this to 5000, so you can see what happens after the window comes up.
 }
 
 /* Functions related to startup */
 function delayedOnLoadMessenger()
 {
+  pref.QueryInterface(Components.interfaces.nsIPrefBranchInternal);
+  pref.addObserver("mail.pane_config.dynamic", MailPaneConfigObserver, false);
   AddMailOfflineObserver();
   CreateMailWindowGlobals();
-  Create3PaneGlobals();
-  AddToolBarPrefListener();
-  ShowHideToolBarButtons();
   verifyAccounts(null);
     
   HideAccountCentral();
@@ -672,15 +766,6 @@ function delayedOnLoadMessenger()
 
   gNotifyDefaultInboxLoadedOnStartup = true;
 
-  // fix for #168937.  now that we don't have a sidebar
-  // users who haven't moved the splitter will
-  // see it jump around
-  var messengerBox = document.getElementById("messengerBox");
-  if (!messengerBox.getAttribute("width")) {
-    messengerBox.setAttribute("width","500px");
-  }
-
-
   //Set focus to the Thread Pane the first time the window is opened.
   SetFocusThreadPane();
 
@@ -695,7 +780,9 @@ function delayedOnLoadMessenger()
 function OnUnloadMessenger()
 {
   accountManager.removeIncomingServerListener(gThreePaneIncomingServerListener);
-  RemoveToolBarPrefListener();
+  pref.QueryInterface(Components.interfaces.nsIPrefBranchInternal);
+  pref.removeObserver("mail.pane_config.dynamic", MailPaneConfigObserver);
+
   // FIX ME - later we will be able to use onload from the overlay
   OnUnloadMsgHeaderPane();
 
@@ -708,11 +795,6 @@ function NotifyObservers(aSubject, aTopic, aData)
   observerService.notifyObservers(aSubject, aTopic, aData);
 }
 
-
-function Create3PaneGlobals()
-{
-}
- 
 // because the "open" state persists, we'll call
 // PerformExpand() for all servers that are open at startup.            
 function PerformExpandForAllOpenServers()
@@ -959,22 +1041,14 @@ function GetTotalCountElement()
 	return totalCount;
 }
 
-function IsThreadAndMessagePaneSplitterCollapsed()
+function IsMessagePaneCollapsed()
 {
-  var messagePane = GetMessagePane();
-  try {
-    return (messagePane.getAttribute("collapsed") == "true");
-  }
-  catch (ex) {
-    return false;
-  }
+  return GetMessagePane().collapsed;
 }
 
 function IsFolderPaneCollapsed()
 {
-  var folderPaneBox = GetFolderTree().parentNode;
-  return folderPaneBox.getAttribute("collapsed") == "true"
-    || folderPaneBox.getAttribute("hidden") == "true";
+  return GetFolderTree().parentNode.collapsed;
 }
 
 function FindMessenger()
diff --git a/mozilla/mail/base/content/widgetglue.js b/mozilla/mail/base/content/widgetglue.js
index 6d0f8149408..6fcc31c561b 100644
--- a/mozilla/mail/base/content/widgetglue.js
+++ b/mozilla/mail/base/content/widgetglue.js
@@ -208,13 +208,7 @@ function FolderProperties(name, uri)
 
 function MsgToggleMessagePane()
 {
-  //OnClickThreadAndMessagePaneSplitter is based on the value before the splitter is toggled.
-  MsgToggleSplitter("threadpane-splitter");
-}
-
-function MsgToggleSplitter(id)
-{
-    var splitter = document.getElementById(id);
+  var splitter = document.getElementById("threadpane-splitter");
     var state = splitter.getAttribute("state");
     if (state == "collapsed")
         splitter.setAttribute("state", null);
diff --git a/mozilla/mail/base/jar.mn b/mozilla/mail/base/jar.mn
index dbb308a6737..cddb1b43411 100644
--- a/mozilla/mail/base/jar.mn
+++ b/mozilla/mail/base/jar.mn
@@ -10,6 +10,7 @@ messenger.jar:
 *+  content/messenger/messageWindow.js              (content/messageWindow.js)
 *+  content/messenger/messenger.xul                 (content/messenger.xul)
 *+  content/messenger/msgMail3PaneWindow.js         (content/msgMail3PaneWindow.js)
+*+  content/messenger/mail3PaneWindowCommands.js    (content/mail3PaneWindowCommands.js)
 *+  content/messenger/mailCore.js                   (content/mailCore.js)
 *+  content/messenger/commandglue.js                (content/commandglue.js)
 *+  content/messenger/widgetglue.js                 (content/widgetglue.js)