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
}
	@PreDestroy
	void contextDisposed() {
		if (eventBroker == null)
			return;
		eventBroker.unsubscribe(toBeRenderedHandler);
		eventBroker.unsubscribe(visibilityHandler);
		eventBroker.unsubscribe(childrenHandler);
		eventBroker.unsubscribe(trimHandler);
	}
	private static void populateModelInterfaces(MContext contextModel,
			IEclipseContext context, Class<?>[] interfaces) {
		for (Class<?> intf : interfaces) {
			Activator.trace(Policy.DEBUG_CONTEXTS,
					"Adding " + intf.getName() + " for " 
							+ contextModel.getClass().getName(), null);
			context.set(intf.getName(), contextModel);
			populateModelInterfaces(contextModel, context, intf.getInterfaces());
		}
	}
	private String getContextName(MUIElement element) {
		StringBuilder builder = new StringBuilder(element.getClass()
				.getSimpleName());
		String elementId = element.getElementId();
		if (elementId != null && elementId.length() != 0) {
			builder.append(" (").append(elementId).append(") ");
		}
		builder.append("Context");
		return builder.toString();
	}