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.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
window.getChildren().add(perspectiveStack);
		window.setSelectedElement(perspectiveStack);
		MPerspective perspectiveA = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspectiveA);
		perspectiveStack.setSelectedElement(perspectiveA);
		MPlaceholder placeholderA = AdvancedFactoryImpl.eINSTANCE
				.createPlaceholder();
		placeholderA.setRef(partA);
		partA.setCurSharedRef(placeholderA);
		perspectiveA.getChildren().add(placeholderA);
		perspectiveA.setSelectedElement(placeholderA);
		MPerspective perspectiveB = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspectiveB);
		MPlaceholder placeholderB = AdvancedFactoryImpl.eINSTANCE
				.createPlaceholder();
		placeholderB.setRef(partB);
		perspectiveB.getChildren().add(placeholderB);
		perspectiveB.setSelectedElement(placeholderB);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = window.getContext().get(EPartService.class);
		partService.switchPerspective(perspectiveB);
		partService.switchPerspective(perspectiveA);
		ClientEditor editorA = (ClientEditor) partA.getObject();
		ClientEditor editorB = (ClientEditor) partB.getObject();
		editorA.focusCalled = false;
		editorB.focusCalled = false;
		partService.switchPerspective(perspectiveB);