I added ComboBox component to the PagingToolBar component to enable user to change number of displayed items in the table. Everytime user changes table row count, he gets following error in IE8 / IE7.

 number: -2146826178 description:
Can't move focus to the control because it is invisible, not enabled, or of a type that does not accept the focus.
I found the problem in ComboxBoxCell.java
protected void onViewClick(final XElement parent, NativeEvent event, boolean focus, boolean takeSelected) {    

    // .... removed some lines for better readability ....

    if (focus) {
      Scheduler.get().scheduleDeferred(new ScheduledCommand() {

        public void execute() {
          if (GXTLogConfiguration.loggingIsEnabled()) {
            logger.finest("onViewClick parent.focus()");

          getInputElement(parent).focus(); // <----- THIS WILL CRASH !!!

I only crashes in IE that cannot handle focusing of the disabled items correctly. This bug does not show in Opera, Firefox or Chrome (Chromium). But because the toolbar is disabled while waiting for loader to finish loading data, focusing of the combox will throw exception.