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.setSelectedElement(perspectiveStack);
		MPerspective perspective = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspective);
		perspectiveStack.setSelectedElement(perspective);
		MPlaceholder placeholder = AdvancedFactoryImpl.eINSTANCE
				.createPlaceholder();
		placeholder.setRef(part);
		placeholder.setToBeRendered(false);
		perspective.getChildren().add(placeholder);
		
		initialize(applicationContext, application);
		
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		partService.hidePart(part, force);
		assertEquals(force, !perspective.getChildren().contains(placeholder));
	}
	public void testHidePart_Bug325148_True() {
		testHidePart_Bug325148(true);
	}
	public void testHidePart_Bug325148_False() {
		testHidePart_Bug325148(false);
	}
	private void testHidePart_Bug325148_Unrendered(boolean force) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MPartDescriptor partDescriptor = org.eclipse.e4.ui.model.application.descriptor.basic.impl.BasicFactoryImpl.eINSTANCE
				.createPartDescriptor();