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
MPart shownPart = partService.showPart(createdPart, partState);
		assertNotNull(shownPart);
		if (multipleAllowed) {
			assertEquals(createdPart, shownPart);
		} else {
			assertEquals(part, shownPart);
		}
	}
	public void testShowPart_Part_MultipleExists_TrueACTIVATE() {
		testShowPart_Part_MultipleExists(true, PartState.ACTIVATE);
	}
	public void testShowPart_Part_MultipleExists_FalseACTIVATE() {
		testShowPart_Part_MultipleExists(false, PartState.ACTIVATE);
	}
	public void testShowPart_Part_MultipleExists_TrueVISIBLE() {
		testShowPart_Part_MultipleExists(true, PartState.VISIBLE);
	}
	public void testShowPart_Part_MultipleExists_FalseVISIBLE() {
		testShowPart_Part_MultipleExists(false, PartState.VISIBLE);
	}
	public void testShowPart_Part_MultipleExists_TrueCREATE() {
		testShowPart_Part_MultipleExists(true, PartState.CREATE);
	}
	public void testShowPart_Part_MultipleExists_FalseCREATE() {
		testShowPart_Part_MultipleExists(false, PartState.CREATE);
	}
	private void testShowPart_Part_MultipleNonexistent(boolean multipleAllowed,
			PartState partState) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();