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/src/org/eclipse/e4/ui/internal/workbench/ModelServiceImpl.java
*/
	private boolean match(MUIElement element, String id, Class clazz, List<String> tagsToMatch) {
		if (id != null && !id.equals(element.getElementId()))
			return false;
		if (clazz != null && !(clazz.isInstance(element)))
			return false;
		if (tagsToMatch != null) {
			List<String> elementTags = element.getTags();
			for (String tag : tagsToMatch) {
				if (!elementTags.contains(tag))
					return false;
			}
		}
		return true;
	}
	private <T> void findElementsRecursive(MUIElement searchRoot, String id,
			Class<? extends T> type, List<String> tagsToMatch, List<T> elements, int searchFlags) {
		if (searchFlags == 0)
			return;
		
		if (match(searchRoot, id, type, tagsToMatch)) {
			if (!elements.contains((T) searchRoot))
				elements.add((T) searchRoot);
		}
		
		if (searchRoot instanceof MElementContainer<?>) {
			if (searchRoot instanceof MPerspectiveStack) {
				if ((searchFlags & IN_ANY_PERSPECTIVE) != 0) {
					
					MElementContainer<MUIElement> container = (MElementContainer<MUIElement>) searchRoot;