Bug 339573 Splitting the shared area with a part doesn't remove stale placeholders
The current code only looks for the addition of an MPlaceholder in the shared area as the hint to remove locals. When you split the area the element that gets added is the new MPartSashContainer...
bundles/org.eclipse.e4.ui.workbench.swt/src/org/eclipse/e4/ui/internal/workbench/swt/PartRenderingEngine.java
};
	private EventHandler childrenHandler = new EventHandler() {
		public void handleEvent(Event event) {
			Object changedObj = event.getProperty(UIEvents.EventTags.ELEMENT);
			if (!(changedObj instanceof MElementContainer<?>))
				return;
			MElementContainer<MUIElement> changedElement = (MElementContainer<MUIElement>) changedObj;
			boolean isApplication = changedObj instanceof MApplication;
			boolean menuChild = changedObj instanceof MMenu;
			
			AbstractPartRenderer renderer = getRendererFor(changedElement);
			if ((!isApplication && renderer == null) || menuChild)
				return;
			String eventType = (String) event
					.getProperty(UIEvents.EventTags.TYPE);
			if (UIEvents.EventTypes.ADD.equals(eventType)) {
				Activator.trace(Policy.DEBUG_RENDERER, "Child Added", null); 
				MUIElement added = (MUIElement) event
						.getProperty(UIEvents.EventTags.NEW_VALUE);
				
				
				
				
				boolean isStack = changedObj instanceof MGenericStack<?>;
				boolean hasWidget = added.getWidget() != null;
				boolean isSelected = added == changedElement
						.getSelectedElement();
				boolean renderIt = !isStack || hasWidget || isSelected;
				if (renderIt) {