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
public void testHidePart_ActivationHistory23() {
		MApplication application = ApplicationFactoryImpl.eINSTANCE
				.createApplication();
		MWindow window = BasicFactoryImpl.eINSTANCE.createWindow();
		application.getChildren().add(window);
		application.setSelectedElement(window);
		MPart partA = BasicFactoryImpl.eINSTANCE.createPart();
		window.getSharedElements().add(partA);
		MPart partB = BasicFactoryImpl.eINSTANCE.createPart();
		window.getSharedElements().add(partB);
		MPart partC = BasicFactoryImpl.eINSTANCE.createPart();
		window.getSharedElements().add(partC);
		MPerspectiveStack perspectiveStack = AdvancedFactoryImpl.eINSTANCE
				.createPerspectiveStack();
		window.getChildren().add(perspectiveStack);
		window.setSelectedElement(perspectiveStack);
		MPerspective perspectiveA = AdvancedFactoryImpl.eINSTANCE
				.createPerspective();
		perspectiveStack.getChildren().add(perspectiveA);
		perspectiveStack.setSelectedElement(perspectiveA);
		MPlaceholder placeholderA1 = AdvancedFactoryImpl.eINSTANCE
				.createPlaceholder();
		placeholderA1.setRef(partA);
		partA.setCurSharedRef(placeholderA1);
		perspectiveA.getChildren().add(placeholderA1);
		perspectiveA.setSelectedElement(placeholderA1);
		MPlaceholder placeholderB1 = AdvancedFactoryImpl.eINSTANCE
				.createPlaceholder();
		placeholderB1.setRef(partB);
		partB.setCurSharedRef(placeholderB1);