Bug 295981 [Forms] FormImages & FormFonts are not disposed correctly
bundles/org.eclipse.ui.forms/src/org/eclipse/ui/internal/forms/widgets/FormHeading.java
Point msize = null;
			Point tbsize = null;
			Point clsize = null;
			if (flushCache) {
				clientCache.flush();
				messageCache.flush();
				toolbarCache.flush();
			}
			if (hasToolBar()) {
				ToolBar tb = toolBarManager.getControl();
				toolbarCache.setControl(tb);
				tbsize = toolbarCache.computeSize(SWT.DEFAULT, SWT.DEFAULT);
			}
			if (headClient != null) {
				clientCache.setControl(headClient);
				int cwhint = width;
				if (cwhint != SWT.DEFAULT) {
					cwhint -= HMARGIN * 2;
					if (tbsize != null && getToolBarAlignment() == SWT.BOTTOM)
						cwhint -= tbsize.x + SPACING;
				}
				clsize = clientCache.computeSize(cwhint, SWT.DEFAULT);
			}
			int totalFlexWidth = width;
			int flexWidth = totalFlexWidth;
			if (totalFlexWidth != SWT.DEFAULT) {
				totalFlexWidth -= TITLE_HMARGIN * 2;
				
				if (hasToolBar() && getToolBarAlignment() == SWT.TOP
						|| hasMessageRegion())