snippet shows how to remove handler registration within anonymous handler

RemoveHandler.java

// http://stackoverflow.com/questions/4715034/gwt-problem-with-handlerregistration/5275448#5275448

final Set<HandlerRegistration> hack = new HashSet<HandlerRegistration>();
((FocusWidget) sourceWidget).setFocus(true);
hack.add(((FocusWidget) sourceWidget).addBlurHandler(new BlurHandler() {
	
	@Override
	public void onBlur(BlurEvent event) {
		ApplicationUtils.getTipsy().hide();
		for (HandlerRegistration hr : hack) {
			hr.removeHandler();
		}
	}
}));
hack.add(((FocusWidget) sourceWidget).addKeyPressHandler(new KeyPressHandler() {
	@Override
	public void onKeyPress(KeyPressEvent event) {
		ApplicationUtils.getTipsy().hide();
		for (HandlerRegistration hr : hack) {
			hr.removeHandler();
		}
	}
}));