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
getEngine().createGui(window);
		EPartService partService = (EPartService) window.getContext().get(
				EPartService.class.getName());
		MPart shownPart = partService.showPart("partId", partState);
		assertEquals(1, window.getChildren().size());
		assertEquals(part, window.getChildren().get(0));
		assertEquals(part, shownPart);
		assertTrue("A shown part should be rendered", part.isToBeRendered());
	}
	public void testShowPart_Id_Unrendered_CREATE() {
		testShowPart_Id_Unrendered(PartState.CREATE);
	}
	public void testShowPart_Id_Unrendered_VISIBLE() {
		testShowPart_Id_Unrendered(PartState.VISIBLE);
	}
	public void testShowPart_Id_Unrendered_ACTIVATE() {
		testShowPart_Id_Unrendered(PartState.ACTIVATE);
	}
	private void testShowPart_Id_Unrendered2(EPartService.PartState partState) {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		window.setToBeRendered(true);
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPartStack partStack = BasicFactoryImpl.eINSTANCE.createPartStack();
		partStack.setToBeRendered(false);
		window.getChildren().add(partStack);
		MPart part = BasicFactoryImpl.eINSTANCE.createPart();
		part.setElementId("partId");