SyncDialog

void OnSyncResponse (object sender, Gtk.ResponseArgs args)
		{
			((Gtk.Widget) sender).Destroy ();
			sync_dlg = null;
		}

		public void ShowSync ()
		{
			//Console.WriteLine("showSync");
			if (sync_dlg == null) {
			sync_dlg = new SyncDialog ();
				sync_dlg.Response += OnSyncResponse;
			}
			sync_dlg.Present ();
		}