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
partService.bringToTop(partBack);
		assertTrue("Bringing a part to the top should cause it to be rendered",
				partBack.isToBeRendered());
	}
	public void testGetParts_Empty() {
		MApplication application = createApplication(1, new String[1][0]);
		MWindow window = application.getChildren().get(0);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		Collection<MPart> parts = partService.getParts();
		assertNotNull(parts);
		assertEquals(0, parts.size());
	}
	public void testGetParts_OneWindow() {
		MApplication application = createApplication("partId", "partId2");
		MWindow window = application.getChildren().get(0);
		MPartStack partStack = (MPartStack) window.getChildren().get(0);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		Collection<MPart> parts = partService.getParts();
		assertNotNull(parts);
		assertEquals(2, parts.size());
		assertTrue(parts.containsAll(partStack.getChildren()));
	}
	public void testGetParts_TwoWindows() {
		MApplication application = createApplication(new String[] { "partId",
				"partId2" }, new String[] { "partIA", "partIdB", "partIdC" });
		MWindow windowA = application.getChildren().get(0);