Bug 295981 [Forms] FormImages & FormFonts are not disposed correctly
bundles/org.eclipse.ui.forms/src/org/eclipse/ui/internal/forms/widgets/FormImages.java
public int hashCode() {
			int hash = 0;
			for (int i = 0; i < fRGBs.length; i++)
				hash = hash * 7 + fRGBs[i].hashCode();
			hash = hash * 7 + fLength;
			return hash;
		}
	}
	
	private class SimpleImageDescriptor extends AbstractImageDescriptor{
		private int fTheight;
		private int fMarginHeight;
		
		SimpleImageDescriptor (Color color1, Color color2,
				int realtheight, int theight, int marginHeight) {
			super(new Color[] {color1, color2}, realtheight);
			fTheight = theight;
			fMarginHeight = marginHeight;
		}
		
		public boolean equals(Object obj) {
			if (obj instanceof SimpleImageDescriptor) {
				SimpleImageDescriptor id = (SimpleImageDescriptor) obj;
				if (super.equals(obj)  &&
						id.fTheight == fTheight && id.fMarginHeight == fMarginHeight)
					return true;
			}
			return false;
		}