Bug 328946 Part activation history may return incorrect candidate if no placeholders could be found in a perspective
1. Window > Open Perspective > Other... > CVS Repository Exploring 2. Hide the 'CVS Repositories' view. 3. The 'History' view should become active, it is not.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
private EventHandler selectedHandler = new EventHandler() {
		public void handleEvent(Event event) {
			
			if (!listeners.isEmpty()) {
				Object oldSelected = event.getProperty(UIEvents.EventTags.OLD_VALUE);
				if (oldSelected instanceof MPlaceholder) {