Bug 282276 [ContatcsDemo] ThemeSwitcher should force a relayout
When switching the Theme the workbench should be instructed to relayout itself because computedSizes() might have changed (e.g different font-heights, ..)
examples/org.eclipse.e4.demo.contacts/src/org/eclipse/e4/demo/contacts/handlers/ThemeUtil.java
if (workbench instanceof Workbench) {
			Workbench wb = (Workbench) workbench;
			final Shell shell = (Shell) wb.getWindow();
			Display display = shell.getDisplay();
			final CSSEngine engine = (CSSEngine) display
					.getData("org.eclipse.e4.ui.css.core.engine");
			display.syncExec(new Runnable() {
				public void run() {
					try {
						URL url = FileLocator.resolve(new URL(
								"platform:/plugin/org.eclipse.e4.demo.contacts/css/"
										+ css));
						InputStreamReader streamReader = new InputStreamReader(
								url.openStream());
						engine.reset();
						engine.parseStyleSheet(streamReader);
						engine.applyStyles(shell, true, false);
					} catch (MalformedURLException e) {
						/
						e.printStackTrace();
					} catch (IOException e) {
						/
						e.printStackTrace();
					}
				}
			});
		}
	}
}