Merge pull request #1662 from GaborApatiNagy/CA-257553

CA-257553: Unexpected error on the Memory tab while running an "Instant VM create" action

XenAdmin/TabPages/BallooningPage.cs

@@ -116,7 +116,10 @@ namespace XenAdmin.TabPages
                 foreach (VM vm in vms)
                     RegisterVMHandlers(vm);
 
+                Program.BeginInvoke(Program.MainWindow, () =>
+                {
                     Rebuild();
+                });
             }
         }