Bug 327933 Unrendering container with invalid selectedElement can cause target element to be unrendered
bundles/org.eclipse.e4.ui.workbench.swt/src/org/eclipse/e4/ui/internal/workbench/swt/PartRenderingEngine.java
public static final String engineURI = "platform:/plugin/org.eclipse.e4.ui.workbench.swt/"
			+ "org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine";
	private static final String defaultFactoryUrl = "platform:/plugin/org.eclipse.e4.ui.workbench.renderers.swt/"
			+ "org.eclipse.e4.ui.workbench.renderers.swt.WorkbenchRendererFactory";
	private String factoryUrl;
	IRendererFactory curFactory = null;
	MenuServiceFilter menuServiceFilter;
	org.eclipse.swt.widgets.Listener keyListener;
	
	private EventHandler toBeRenderedHandler = new EventHandler() {
		public void handleEvent(Event event) {
			MUIElement changedElement = (MUIElement) event
					.getProperty(UIEvents.EventTags.ELEMENT);