Bug 328339 Part activation history seems to ignore detached windows
1. Detach a view. 2. Drag another view into said detached window. 3. Activate the two views alternatively. 4. Close one of them. 5. A part in the workbench window is activated instead of the other view in the detached window.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
stack.getChildren().add(placeholderA);
		stack.setSelectedElement(placeholderA);
		MPlaceholder placeholderB = AdvancedFactoryImpl.eINSTANCE
				.createPlaceholder();
		partB.setCurSharedRef(placeholderB);
		placeholderB.setRef(partB);
		stack.getChildren().add(placeholderB);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = window.getContext().get(EPartService.class);
		partService.activate(partA);
		partService.hidePart(partA);
		assertEquals(placeholderB, stack.getSelectedElement());
		assertEquals(partB, partService.getActivePart());
		partService.hidePart(partB);
		assertNull(stack.getSelectedElement());
		assertNull(partService.getActivePart());
	}
	public void testHidePart_ActivationHistory08() {
		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);
		MPerspectiveStack perspectiveStack = AdvancedFactoryImpl.eINSTANCE
				.createPerspectiveStack();
		window.getChildren().add(perspectiveStack);
		window.setSelectedElement(perspectiveStack);