Bug 329184 Detached view that is an activation target candidate can prevent perspective switching
1. Detach the 'Outline' view. 2. Window > Open Perspective > Debug 3. Window > Open Perspective > Java 4. The perspective switch doesn't actually happen. You see the 'Debug' perspective's content with an 'Outline' view detached. Closing the 'Outline' view in the 'Debug' perspective will workaround this problem.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
part.setToBeRendered(false);
		partStack.getChildren().add(part);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		MPart shownPart = partService.showPart("partId", partState);
		assertEquals(1, partStack.getChildren().size());
		assertEquals(part, partStack.getChildren().get(0));
		assertEquals(part, shownPart);
		assertTrue("A shown part should be rendered", part.isToBeRendered());
	}
	public void testShowPart_Id_Unrendered_CREATE2() {
		testShowPart_Id_Unrendered2(PartState.CREATE);
	}
	public void testShowPart_Id_Unrendered_VISIBLE2() {
		testShowPart_Id_Unrendered2(PartState.VISIBLE);
	}
	public void testShowPart_Id_Unrendered_ACTIVATE2() {
		testShowPart_Id_Unrendered2(PartState.ACTIVATE);
	}
	private void testShowPart_Id_Unrendered3(EPartService.PartState partState) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		window.setToBeRendered(true);
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPartSashContainer partSashContainer = BasicFactoryImpl.eINSTANCE
				.createPartSashContainer();