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
}
				}
			}
			
			if (element.getParent() instanceof MUIElement) {
				MElementContainer<MUIElement> parentElement = element
						.getParent();
				AbstractPartRenderer parentRenderer = getRendererFor(parentElement);
				if (parentRenderer != null)
					parentRenderer.childRendered(parentElement, element);
			}
			return element.getWidget();
		}
		if (element instanceof MContext) {
			MContext ctxt = (MContext) element;
			
			
			if (ctxt.getContext() == null) {
				IEclipseContext lclContext = parentContext
						.createChild(getContextName(element));
				populateModelInterfaces(ctxt, lclContext, element.getClass()
						.getInterfaces());
				ctxt.setContext(lclContext);
				
				
				
				
				for (String variable : ctxt.getVariables()) {
					lclContext.declareModifiable(variable);
				}