setSelectOnFocus not working when using mask

[gvangass]

A FormItem's setSelectOnFocus does not work when a mask is applied to it.
I've even tried something like:

birthdate.addFocusHandler(new FocusHandler(){
	@Override
	public void onFocus(FocusEvent event) {
		DeferredCommand.addCommand(new Command(){
			@Override
			public void execute() {
				birthdate.setSelectionRange(1, 10);
			}
		});
	}
});

Is there maybe a way to force a select ?