Bug 326087 StackRenderer arbitrarily changes selected element when MPartStack is being unrendered
1. Open two files. 2. Activate the editor in the back. 3. Restart 4. The file in the wrong is active now. :O
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/StackRenderer.java
}
	public StackRenderer() {
		super();
	}
	@PostConstruct
	public void init() {
		super.init(eventBroker);
		itemUpdater = new EventHandler() {
			public void handleEvent(Event event) {
				MUIElement element = (MUIElement) event
						.getProperty(UIEvents.EventTags.ELEMENT);
				if (!(element instanceof MPart))
					return;
				MPart part = (MPart) element;
				String attName = (String) event
						.getProperty(UIEvents.EventTags.ATTNAME);
				Object newValue = event
						.getProperty(UIEvents.EventTags.NEW_VALUE);
				
				if (element.getParent() != null
						&& element.getParent().getRenderer() == StackRenderer.this) {
					CTabItem cti = findItemForPart(element, element.getParent());
					if (cti != null) {
						updateTab(cti, part, attName, newValue);
					}
					return;
				}
				
				
				List<MPlaceholder> refs = ElementReferenceRenderer