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
MPart sharedPart = (MPart) placeholder.getRef();
		sharedPart.setCurSharedRef(placeholder);
		placeholder.setToBeRendered(false);
		sharedPart.setToBeRendered(false);
		perspective.getChildren().add(placeholder);
		partService.showPart(sharedPart, partState);
		assertNotNull(perspective.getSelectedElement());
		assertEquals(placeholder, perspective.getSelectedElement());
	}
	public void testShowPart_Bug322368_Placeholder_ACTIVATE() {
		testShowPart_Bug322368_Placeholder(PartState.ACTIVATE);
	}
	public void testShowPart_Bug322368_Placeholder_VISIBLE() {
		testShowPart_Bug322368_Placeholder(PartState.VISIBLE);
	}
	public void testShowPart_Bug322368_Placeholder_CREATE() {
		testShowPart_Bug322368_Placeholder(PartState.CREATE);
	}
	public void testShowPart_Bug322403_A() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MPartDescriptor partDescriptor = org.eclipse.e4.ui.model.application.descriptor.basic.impl.BasicFactoryImpl.eINSTANCE
				.createPartDescriptor();
		partDescriptor.setElementId("partId");
		partDescriptor.setAllowMultiple(true);
		application.getDescriptors().add(partDescriptor);
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPerspectiveStack perspectiveStack = AdvancedFactoryImpl.eINSTANCE