Bug 295644: endBatchTransaction() should call updateUndoRedoMenu().

patch by jminta, r=mvl

calendar/resources/content/calendar.js

@@ -1480,6 +1480,7 @@ function startBatchTransaction() {
 }
 function endBatchTransaction() {
     gTransactionMgr.endBatch();
+    updateUndoRedoMenu();
 }
 
 function canUndo() {