fix for #32249. make newsgroups threaded by default. sr=bienvenu

mailnews/base/resources/content/commandglue.js

@@ -96,8 +96,13 @@ function ChangeFolderByDOMNode(folderNode)
   }
   var uri = folderNode.getAttribute('id');
   dump(uri + "\n");
-  
+
   var isThreaded = folderNode.getAttribute('threaded');
+
+  if ((isThreaded == "") && isNewsURI(uri)) {
+    isThreaded = "true";
+  }
+
   var sortResource = folderNode.getAttribute('sortResource');
   if(!sortResource)
 	sortResource = "";
@@ -212,6 +217,16 @@ function ChangeFolderByURI(uri, isThreaded, sortID, sortDirection)
   }
 }
 
+function isNewsURI(uri)
+{
+    if (uri[0] != 'n') {
+        return false;
+    }
+    else {
+        return (uri.substring(0,6) == "news:/");
+    }
+}
+
 function RerootFolder(uri, newFolder, isThreaded, sortID, sortDirection)
 {
   dump('In reroot folder\n');
@@ -250,7 +265,7 @@ function RerootFolder(uri, newFolder, isThreaded, sortID, sortDirection)
 
   //Clear out the thread pane so that we can sort it with the new sort id without taking any time.
   folder.setAttribute('ref', "");
-   if ( uri.substring(0,6) == "news:/" )
+   if (isNewsURI(uri))
        SetNewsFolderColumns(true);
    else
        SetNewsFolderColumns(false);

mailnews/base/resources/content/mailWindowOverlay.js

@@ -237,8 +237,7 @@ function MsgDeleteMessage(reallyDelete, fromToolbar)
     {
         var folderResource = srcFolder.QueryInterface(Components.interfaces.nsIRDFResource);
         var uri = folderResource.Value;
-        //dump("uri[0:6]=" + uri.substring(0,6) + "\n");
-        if (uri.substring(0,6) == "news:/")
+        if (isNewsURI(uri))
         {
             //dump("delete ignored!\n");
             return;
@@ -286,7 +285,7 @@ function MsgMoveMessage(destFolder)
 
         var srcResource = srcFolder.QueryInterface(Components.interfaces.nsIRDFResource);
         var srcUri = srcResource.Value;
-        if (srcUri.substring(0,6) == "news:/")
+        if (isNewsURI(srcUri))
         {
             CopyMessages(compositeDataSource, srcFolder, destMsgFolder, messages, false);
         }

mailnews/base/resources/content/messengerdnd.js

@@ -252,8 +252,7 @@ function DropOnFolderTree(event)
 		messageList.AppendElement(sourceNode);
 	}
 
-    if (sourceID.substring(0,6) == "news:/")
-		isNews = true;
+	isNews = isNewsURI(sourceID);
 
 	var targetNode = RDF.GetResource(targetID, true);
 	if (!targetNode)	return(false);

mailnews/base/resources/content/threadPane.js

@@ -191,7 +191,7 @@ function ChangeThreadView()
 		{
 			ShowThreads(false);
 			if(folder)
-				folder.setAttribute('threaded', "");
+				folder.setAttribute('threaded', "false");
 			SetTemplateTreeItemOpen(false);
 		}
 		else if(currentView == 'unthreaded')