add helper function GetFirstSelectedMsgFolder(), and fix the ".len" vs ".length" problem

to get subscribe, new folder, and rename folder to work again.  also some more debugging
dumps.  r=putterman.

mailnews/base/resources/content/mailWindowOverlay.js

@@ -124,10 +124,7 @@ function MsgHome(url)
 function MsgNewFolder()
 {
 	var windowTitle = Bundle.GetStringFromName("newFolderDialogTitle");
-	var selectedFolders = GetSelectedMsgFolders();
-	var preselectedFolder = null;
-	if(selectedFolders.len > 0)
-		preselectedFolder = selectedFolders[0];
+	var preselectedFolder = GetFirstSelectedMsgFolder();
 
 	CreateNewSubfolder("chrome://messenger/content/newFolderNameDialog.xul",windowTitle, preselectedFolder);
 }
@@ -146,11 +143,7 @@ function MsgSubscribe()
 		useRealSubscribeDialog = false;
 	}
 
-	var selectedFolders = GetSelectedMsgFolders();
-	var preselectedFolder = null;
-	if(selectedFolders.len > 0)
-		preselectedFolder = selectedFolders[0];
-
+	var preselectedFolder = GetFirstSelectedMsgFolder();
 	if (useRealSubscribeDialog)  {
 			Subscribe(windowTitle, preselectedFolder);
 	}

mailnews/base/resources/content/msgMail3PaneWindow.js

@@ -1162,6 +1162,17 @@ function GetSelectedMsgFolders()
 	return folderArray;
 }
 
+function GetFirstSelectedMsgFolder()
+{
+	var result = null;
+	var selectedFolders = GetSelectedMsgFolders();
+	if (selectedFolders.length > 0) {
+		result = selectedFolders[0];
+	}
+
+	return result;
+}
+
 function GetSelectedMessages()
 {
 	var threadTree = GetThreadTree();

mailnews/base/resources/content/subscribe.js

@@ -15,6 +15,7 @@ function Stop()
 
 function SetUpTree()
 {
+	dump("SetUpTree()\n");
 	var nntpService = Components.classes['component://netscape/messenger/nntpservice'].getService(Components.interfaces.nsINntpService);
 	nntpService = nntpService.QueryInterface(Components.interfaces.nsINntpService);
 	nntpService.buildSubscribeDatasource(gCurrentServer);
@@ -28,7 +29,7 @@ function SubscribeOnLoad()
 {
 	dump("SubscribeOnLoad()\n");
 	
-    gSubscribeTree = document.getElementById('subscribetree');
+    	gSubscribeTree = document.getElementById('subscribetree');
 
 	doSetOKCancel(subscribeOK,subscribeCancel);
 
@@ -45,6 +46,7 @@ function SubscribeOnLoad()
 	
 	if (window.arguments[0].preselectedURI) {
 		gServerURI = window.arguments[0].preselectedURI;
+		dump("subscribe: got a uri," + gServerURI + "\n");
 		folder = GetMsgFolderFromUri(window.arguments[0].preselectedURI);
 		gCurrentServer = folder.server;
 
@@ -55,6 +57,9 @@ function SubscribeOnLoad()
 		
 		SubscribeDS = RDF.GetDataSource("rdf:subscribe");
 	}
+	else {
+		dump("subscribe: no uri\n");
+	}
 }
 
 function subscribeOK()