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
public void testHidePart_Tagged_True() {
		testHidePart_Tagged(true);
	}
	public void testHidePart_Tagged_False() {
		testHidePart_Tagged(false);
	}
	public void testGetDirtyParts() {
		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> dirtyParts = partService.getDirtyParts();
		assertNotNull(dirtyParts);
		assertEquals(0, dirtyParts.size());
	}
	public void testGetDirtyParts2() {
		MApplication application = createApplication("partId");
		MWindow window = application.getChildren().get(0);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		Collection<MPart> dirtyParts = partService.getDirtyParts();
		assertNotNull(dirtyParts);
		assertEquals(0, dirtyParts.size());
	}
	private void testGetDirtyParts3(boolean before, boolean after) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();