Bug 295981 [Forms] FormImages & FormFonts are not disposed correctly
bundles/org.eclipse.ui.forms/src/org/eclipse/ui/internal/forms/widgets/FormHeading.java
setBackgroundMode(SWT.INHERIT_DEFAULT);
		addListener(SWT.Paint, new Listener() {
			public void handleEvent(Event e) {
				onPaint(e.gc);
			}
		});
		addListener(SWT.Dispose, new Listener() {
			public void handleEvent(Event e) {
				if (gradientImage != null) {
					FormImages.getInstance().markFinished(gradientImage);
					gradientImage = null;
				}
			}
		});
		addListener(SWT.Resize, new Listener() {
			public void handleEvent(Event e) {
				if (gradientInfo != null
						|| (backgroundImage != null && !isBackgroundImageTiled()))
					updateGradientImage();
			}
		});
		addMouseMoveListener(new MouseMoveListener() {
			public void mouseMove(MouseEvent e) {
				updateTitleRegionHoverState(e);
			}
		});
		addMouseTrackListener(new MouseTrackListener() {
			public void mouseEnter(MouseEvent e) {
				updateTitleRegionHoverState(e);
			}