public void run() {
			Image unchecked = (Image) display.getData (ID_UNCHECKED);
			if (unchecked != null) unchecked.dispose ();
			Image grayUnchecked = (Image) display.getData (ID_GRAYUNCHECKED);
			if (grayUnchecked != null) grayUnchecked.dispose ();
			Image checkmark = (Image) display.getData (ID_CHECKMARK);
			if (checkmark != null) checkmark.dispose ();
			Image arrowDown = (Image) display.getData (ID_ARROWDOWN);
			if (arrowDown != null) arrowDown.dispose ();
			Image arrowUp = (Image) display.getData (ID_ARROWUP);
			if (arrowUp != null) arrowUp.dispose ();

			display.setData (ID_UNCHECKED, null);
			display.setData (ID_GRAYUNCHECKED, null);
			display.setData (ID_CHECKMARK, null);
			display.setData (ID_ARROWDOWN, null);
			display.setData (ID_ARROWUP, null);
		}