Bug 337002 EPartService leaks previously active part
A reference is kept to the previously active part. This is unnecessary. We only need it to fire events. After the deactivation events have been fired, we should no longer need to keep it lying around.
tests/org.eclipse.e4.ui.tests/src/org/eclipse/e4/ui/tests/application/EPartServiceTest.java
part.setToBeRendered(false);
		partStack.getChildren().add(part);
		initialize(applicationContext, application);
		getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		MPart shownPart = partService.showPart("partId", partState);
		assertEquals(1, partStack.getChildren().size());
		assertEquals(part, partStack.getChildren().get(0));
		assertEquals(part, shownPart);
		assertTrue("A shown part should be rendered", part.isToBeRendered());
	}
	public void testShowPart_Id_Unrendered_CREATE2() {
		testShowPart_Id_Unrendered2(PartState.CREATE);
	}
	public void testShowPart_Id_Unrendered_VISIBLE2() {
		testShowPart_Id_Unrendered2(PartState.VISIBLE);
	}
	public void testShowPart_Id_Unrendered_ACTIVATE2() {
		testShowPart_Id_Unrendered2(PartState.ACTIVATE);
	}
	private void testShowPart_Id_Unrendered3(EPartService.PartState partState) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		window.setToBeRendered(true);
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPartSashContainer partSashContainer = BasicFactoryImpl.eINSTANCE
				.createPartSashContainer();