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.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
private void firePartVisible(MPart part) {
		for (Object listener : listeners.getListeners()) {
			((IPartListener) listener).partVisible(part);
		}
	}
	private void firePartBroughtToTop(MPart part) {
		for (Object listener : listeners.getListeners()) {
			((IPartListener) listener).partBroughtToTop(part);
		}
	}
	public void addPartListener(IPartListener listener) {
		listeners.add(listener);
	}
	public void removePartListener(IPartListener listener) {
		listeners.remove(listener);
	}
	private MWindow getWindow() {
		if (workbenchWindow != null)
			return workbenchWindow;
		if (application.getSelectedElement() != null)
			return application.getSelectedElement();
		List<MWindow> windows = application.getChildren();
		if (windows.size() != 0)
			return windows.get(0);
		return null;
	}
	private MContext getParentWithContext(MUIElement part) {
		MElementContainer<MUIElement> parent = part.getParent();
		MUIElement intermediate = parent;
		if (intermediate == null) {