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
assertEquals(partB, partService.getActivePart());
		partService.activate(partC);
		assertEquals(partC, partService.getActivePart());
		partService.switchPerspective(perspectiveA);
		assertEquals(partA, partService.getActivePart());
		partService.hidePart(partB, force);
		assertFalse(placeholderB1.isToBeRendered());
	}
	public void testHidePart_Bug327917_True() {
		testHidePart_Bug327917(true);
	}
	public void testHidePart_Bug327917_False() {
		testHidePart_Bug327917(false);
	}
	private void testHidePart_Bug327964(boolean force) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MArea area = AdvancedFactoryImpl.eINSTANCE.createArea();
		window.getSharedElements().add(area);
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		window.getSharedElements().add(part);
		MPerspectiveStack perspectiveStack = AdvancedFactoryImpl.eINSTANCE
				.createPerspectiveStack();
		window.getChildren().add(perspectiveStack);
		window.setSelectedElement(perspectiveStack);
		MPerspective perspective = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();