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
.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		part.setVisible(visible);
		window.getChildren().add(part);
		if (selected) {
			window.setSelectedElement(part);
		}
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		assertEquals(visible, partService.isPartVisible(part));
		partService = (EPartService) part.getContext().get(
				EPartService.class.getName());
		assertEquals(visible, partService.isPartVisible(part));
	}
	public void testIsPartVisible_NotInStackTrueTrue() {
		testIsPartVisible_NotInStack(true, true);
	}
	public void testIsPartVisible_NotInStackFalseTrue() {
		testIsPartVisible_NotInStack(false, true);
	}
	public void testIsPartVisible_NotInStackFalseFalse() {
		testIsPartVisible_NotInStack(false, false);
	}
	public void testIsPartVisible_ViewVisible() {
		MApplication application = createApplication("partId");