fix for #67088. sr=bienvenu.

1) on batch deletes, we quickly bail out of ThreadPaneSelectionChange()
2) we only call document.commandDispatcher.updateCommands('threadTree-select');
once per delete, next, move, selection, folder loading.
3) general cleanup

mailnews/base/resources/content/commandglue.js

@@ -30,7 +30,7 @@ var gBeforeFolderLoadTime;
 var gRDFNamespace = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";
 function OpenURL(url)
 {
-  dump("\n\nOpenURL from XUL\n\n\n");
+  //dump("\n\nOpenURL from XUL\n\n\n");
   messenger.SetWindow(window, msgWindow);
   messenger.OpenURL(url);
 }
@@ -61,10 +61,7 @@ function GetMsgFolderFromURI(folderURI)
 function LoadMessage(messageNode)
 {
 	var uri = messageNode.getAttribute('id');
-	dump(uri + "\n");
-
 	LoadMessageByUri(uri);
-
 }
 
 function LoadMessageByUri(uri)
@@ -759,8 +756,9 @@ function LoadSelectionIntoMessagePane()
 	var tree = GetThreadTree();
 	
 	var selArray = tree.selectedItems;
-	if (!gNextMessageAfterDelete && selArray && (selArray.length == 1) )
+	if (!gNextMessageAfterDelete && selArray && (selArray.length == 1) ) {
 		LoadMessage(selArray[0]);
+    }
 	else
   {
     // don't necessarily clear the message pane...if you uncomment this,
@@ -957,7 +955,6 @@ function SelectNextMessage(nextMessage)
 {
 	var tree = GetThreadTree();
 	ChangeSelection(tree, nextMessage);
-
 }
 
 function GetSelectTrashUri(folder)

mailnews/base/resources/content/mailWindowOverlay.js

@@ -309,7 +309,7 @@ function MsgDeleteMessage(reallyDelete, fromToolbar)
     var compositeDataSource = GetCompositeDataSource("DeleteMessages");
     var messages = GetSelectedMessages();
 
-    SetNextMessageAfterDelete(null, true);
+    SetNextMessageAfterDelete();
     DeleteMessages(compositeDataSource, srcFolder, messages, reallyDelete);
 }
 
@@ -351,8 +351,7 @@ function MsgMoveMessage(destFolder)
         }
         else
         {
-            SetNextMessageAfterDelete(null, true);
-
+            SetNextMessageAfterDelete();
             CopyMessages(compositeDataSource, srcFolder, destMsgFolder, messages, true);
         }
     }    

mailnews/base/resources/content/messageWindow.js

@@ -324,10 +324,7 @@ function GetCompositeDataSource(command)
 	return gCompositeDataSource;	
 }
 
-//Sets the next message after a delete.  If useSelection is true then use the
-//current selection to determine this.  Otherwise use messagesToCheck which will
-//be an array of nsIMessage's.
-function SetNextMessageAfterDelete(messagesToCheck, useSelection)
+function SetNextMessageAfterDelete()
 {
 	gCurrentMessageIsDeleted = true;
 }

mailnews/base/resources/content/messengerdnd.js

@@ -291,7 +291,7 @@ function DropOnFolderTree(event)
 				messageTree = GetThreadTree();
 				nextMessage = GetNextMessageAfterDelete(messageTree.selectedItems);
 				if(nextMessage)
-					gNextMessageAfterDelete = nextMessage.getAttribute('id');
+                    gNextMessageAfterDelete = nextMessage.getAttribute('id');
 				else
 					gNextMessageAfterDelete = null;
 			}

mailnews/base/resources/content/msgMail3PaneWindow.js

@@ -49,6 +49,8 @@ var gStartFolderUri = null;
 //If we've loaded a message, set to true.  Helps us keep the start page around.
 var gHaveLoadedMessage;
 
+var gBatching = false;
+
 // the folderListener object
 var folderListener = {
     OnItemAdded: function(parentItem, item, view) {},
@@ -95,7 +97,9 @@ var folderListener = {
 	OnItemPropertyFlagChanged: function(item, property, oldFlag, newFlag) {},
 
     OnItemEvent: function(folder, event) {
-        if (event.GetUnicode() == "FolderLoaded") {
+        var eventType = event.GetUnicode();
+
+        if (eventType == "FolderLoaded") {
             
 		if(folder)
 		{
@@ -155,10 +159,10 @@ var folderListener = {
 			}
 
 		}
-        } else if (event.GetUnicode() == "DeleteOrMoveMsgCompleted") {
+        } else if (eventType == "DeleteOrMoveMsgCompleted") {
 			HandleDeleteOrMoveMsgCompleted(folder);
         }     
-          else if (event.GetUnicode() == "DeleteOrMoveMsgFailed") {
+          else if (eventType == "DeleteOrMoveMsgFailed") {
                         HandleDeleteOrMoveMsgFailed(folder);
         }
 
@@ -167,30 +171,35 @@ var folderListener = {
 
 function HandleDeleteOrMoveMsgFailed(folder)
 {
+  if(IsCurrentLoadedFolder(folder)) {
+    if(gNextMessageAfterDelete) {
+      gNextMessageAfterDelete = null;
+    }
+  }
 
-        if(IsCurrentLoadedFolder(folder))
-        {
-                if(gNextMessageAfterDelete)
-                {
-                        gNextMessageAfterDelete = null;
-		}
-        }
+  if (gBatching) {
+    gBatching = false;
+    var threadTree = GetThreadTree();
+    //threadTree.treeBoxObject.endBatch();
+    dump("XXX end tree batch (delete or move failed)\n");
+  }
 
+  ThreadPaneSelectionChange(true);
 }
 
 
 function HandleDeleteOrMoveMsgCompleted(folder)
 {
+	var threadTree = GetThreadTree();
 
 	if(IsCurrentLoadedFolder(folder))
 	{
 		msgNavigationService.EnsureDocumentIsLoaded(document);
 		if(gNextMessageAfterDelete)
 		{
-			var nextMessage = document.getElementById(gNextMessageAfterDelete);
+            var nextMessage = document.getElementById(gNextMessageAfterDelete);
 			gNextMessageAfterDelete = null;
 			SelectNextMessage(nextMessage);
-			var threadTree = GetThreadTree();
 			if(threadTree)
 				threadTree.ensureElementIsVisible(nextMessage);
 		}
@@ -205,6 +214,13 @@ function HandleDeleteOrMoveMsgCompleted(folder)
 		}
 	}
 
+    if (gBatching) {
+      gBatching = false;
+      //threadTree.treeBoxObject.endBatch();
+      dump("XXX end tree batch (delete or move succeeded)\n");
+    }
+
+    ThreadPaneSelectionChange(true);
 }
 
 
@@ -229,6 +245,7 @@ function IsCurrentLoadedFolder(folder)
 /* Functions related to startup */
 function OnLoadMessenger()
 {
+  showPerformance = pref.GetBoolPref('mail.showMessengerPerformance');
   var beforeLoadMessenger;
   if(showPerformance) {
       beforeLoadMessenger = new Date();
@@ -324,11 +341,8 @@ function OnUnloadMessenger()
 
 function Create3PaneGlobals()
 {
-	showPerformance = pref.GetBoolPref('mail.showMessengerPerformance');
-
 	msgNavigationService = Components.classes['@mozilla.org/messenger/msgviewnavigationservice;1'].getService();
 	msgNavigationService= msgNavigationService.QueryInterface(Components.interfaces.nsIMsgViewNavigationService);
-
 }
 
 
@@ -938,20 +952,22 @@ function GetCompositeDataSource(command)
 
 }
 
-//Sets the next message after a delete.  If useSelection is true then use the
-//current selection to determine this.  Otherwise use messagesToCheck which will
-//be an array of nsIMessage's.
-function SetNextMessageAfterDelete(messagesToCheck, useSelection)
+function SetNextMessageAfterDelete()
 {
-	if(useSelection)
-	{
-		var tree = GetThreadTree();
-		var nextMessage = GetNextMessageAfterDelete(tree.selectedItems);
-		if(nextMessage)
-			gNextMessageAfterDelete = nextMessage.getAttribute('id');
-		else
-			gNextMessageAfterDelete = null;
-	}
+	var tree = GetThreadTree();
+
+	var nextMessage = GetNextMessageAfterDelete(tree.selectedItems);
+	if(nextMessage)
+        gNextMessageAfterDelete = nextMessage.getAttribute('id');
+	else
+		gNextMessageAfterDelete = null;
+
+   // use the magic number of 3 to determine if we want to batch or not.
+   if (!gBatching && (GetNumSelectedMessages() > 3)) {
+     gBatching = true;
+     //tree.treeBoxObject.beginBatch();
+     dump("XXX begin tree batch\n");
+   }
 }
 
 function SelectFolder(folderUri)
@@ -964,7 +980,6 @@ function SelectFolder(folderUri)
 
 function SelectMessage(messageUri)
 {
-    dump("SelectMessage: " + messageUri + "\n");
 	var tree = GetThreadTree();
 	var treeitem = document.getElementById(messageUri);
 	if(tree && treeitem)

mailnews/base/resources/content/msgViewNavigation.js

@@ -197,7 +197,6 @@ function GoPreviousMessage(type, startFromEnd)
 // gotoNextInThread is true if once we find an unrad thread we should select the first message in that thread that fits criteria
 function GoNextThread(type, startFromBeginning, gotoNextInThread)
 {
-
 	if(messageView.showThreads)
 	{
 		var tree = GetThreadTree();

mailnews/base/resources/content/threadPane.js

@@ -18,7 +18,8 @@
  * Rights Reserved.
  */
 
-var gOldNumSelected = 0;
+var gLastMessageUriToLoad = null;
+
 function ThreadPaneOnClick(event)
 {
     var t = event.originalTarget;
@@ -223,29 +224,51 @@ function IsSpecialFolderSelected(folderName)
 }
 
 //Called when selection changes in the thread pane.
-function ThreadPaneSelectionChange()
+function ThreadPaneSelectionChange(fromDeleteOrMoveHandler)
 {
+    // we are batching.  bail out, we'll be back when the batch is over
+    if (gBatching) return;
+
 	var collapsed = IsThreadAndMessagePaneSplitterCollapsed();
 
-	if(!collapsed)
-	{
-		LoadSelectionIntoMessagePane();
-		
-	}
-
-	var tree = GetThreadTree();
+    var tree = GetThreadTree();
 	var selectedMessages = tree.selectedItems;
 	var numSelected = selectedMessages.length;
-	//If the current selected is 1 or 0 then we know that a change has taken place that might
-	//cause us to send out threadTree update notifications. We also care about this if the previous
-	//numSelected was 0 or 1 because we might be involved in something like a SelectAll where we won't
-	//get notified about the change from 0 to 1.
-	if(numSelected == 0 || numSelected == 1 || gOldNumSelected == 0 || gOldNumSelected == 1)
-	{
-		document.commandDispatcher.updateCommands('threadTree-select');
+    var messageUriToLoad = null;
+
+    if (!gNextMessageAfterDelete && selectedMessages && (numSelected == 1) ) {
+        messageUriToLoad = selectedMessages[0].getAttribute('id');
+    }
+
+    // if the message pane isn't collapsed, and we have a message to load
+    // go ahead and load the message
+	if (!collapsed && messageUriToLoad) {
+        LoadMessageByUri(messageUriToLoad);
 	}
-	//Store the current number selected.
-	gOldNumSelected = numSelected;
+
+    // if gNextMessageAfterDelete is true, we can skip updating the commands because
+    // we'll be coming back to load that message, and we'll update the commands then
+    //
+    // if fromDeleteOrMoveHandler is true, we are calling ThreadPaneSelectionChange after handling
+    // a message delete or message move, so we might need to update the commands.  (see below)
+    //
+    // if gCurrentLoadingFolderURI is non null, we are loading a folder, so we need to update the commands
+    //
+    // if messageUriToLoad is non null, we are loading a message, so we might need to update commmands.  (see below)
+	if (!gNextMessageAfterDelete && (gCurrentLoadingFolderURI || fromDeleteOrMoveHandler || messageUriToLoad)) {
+        // if we are moving or deleting, we'll come in here twice.  once to load the message and once when
+        // we are done moving or deleting.  when we loaded the message the first time, we called updateCommands().
+        // there is no need to do it again.
+        if (fromDeleteOrMoveHandler && messageUriToLoad && (messageUriToLoad == gLastMessageUriToLoad)) {
+            // skip the call to updateCommands()
+        }
+        else {
+		    document.commandDispatcher.updateCommands('threadTree-select');
+        }
+	}
+
+	//remember the last message we loaded
+    gLastMessageUriToLoad = messageUriToLoad;
 }
 
 function GetThreadTree()

mailnews/base/resources/content/threadPane.xul

@@ -36,7 +36,7 @@ Rights Reserved.
               onclick="ThreadPaneOnClick(event);"
               ondraggesture="return BeginDragThreadTree(event);"
               ondragdrop="return DropOnThreadTree(event);" 
-	  		  onselect="top.ThreadPaneSelectionChange();"
+	  		  onselect="top.ThreadPaneSelectionChange(false);"
 			  onkeypress="ThreadPaneKeyPress(event);"
               onblur="goOnEvent(this,'blur')"
               containment="http://home.netscape.com/NC-rdf#MessageChild"