Bug 319169 [UI] active parts in Detached windows prevent activating a part in the main window
Start with a fresh WS Detach the Outline view using DnD Now you can no longer activate any part in the main window (i.e. Package Explorer). The cause seems to be that the 'rootContainer' has become the DW's MTrimmedWindow rather than the DW's containing MPerspective. This causes the PartService's 'activate' to fail the 'isInContainer()' test...
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
application.getDescriptors().add(partDescriptor);
		stack.setSelectedElement(part);
		window.setSelectedElement(stack);
		application.setSelectedElement(window);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		MPart shownPart = partService.showPart("partId", partState);
		assertNotNull(shownPart);
		assertEquals(part, shownPart);
	}
	public void testShowPart_Id_MultipleExists_TrueACTIVATE() {
		testShowPart_Id_MultipleExists(true, PartState.ACTIVATE);
	}
	public void testShowPart_Id_MultipleExists_FalseACTIVATE() {
		testShowPart_Id_MultipleExists(false, PartState.ACTIVATE);
	}
	public void testShowPart_Id_MultipleExists_TrueVISIBLE() {
		testShowPart_Id_MultipleExists(true, PartState.VISIBLE);
	}
	public void testShowPart_Id_MultipleExists_FalseVISIBLE() {
		testShowPart_Id_MultipleExists(false, PartState.VISIBLE);
	}
	public void testShowPart_Id_MultipleExists_TrueCREATE() {
		testShowPart_Id_MultipleExists(true, PartState.CREATE);
	}
	public void testShowPart_Id_MultipleExists_FalseCREATE() {
		testShowPart_Id_MultipleExists(false, PartState.CREATE);
	}
	public void testShowPart_Id_PartInInactivePerspective() {