Bug 316298 [Compatibility] Support o.e.ui.menus visibleWhen
We need support in MCoreExpression for entire expressions created by the WorkbenchMenuService. They don't often use ReferenceExpressions to core expression definitions. PW
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/MenuItemRenderer.java
itemContext.runAndTrack(rat);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.internal.workbench.swt.AbstractPartRenderer#hideChild
	 * (org.eclipse.e4.ui.model.application.MElementContainer,
	 * org.eclipse.e4.ui.model.application.MUIElement)
	 */
	@Override
	public void hideChild(MElementContainer<MUIElement> parentElement,
			MUIElement child) {
		super.hideChild(parentElement, child);
		
		
		Widget widget = (Widget) child.getWidget();
		if (widget != null && !widget.isDisposed())
			widget.dispose();
		menuItemToExpression.remove(child);
		VisibleRAT rat = menuItemToRAT.remove(child);
		if (rat != null) {
			rat.participating = false;
		}
	}
	protected void setItemText(MMenuItem model, MenuItem item) {
		String text = model.getLabel();
		if (text == null) {
			text = ""; 
		}