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.swt/src/org/eclipse/e4/ui/workbench/swt/modeling/MenuServiceFilter.java
break;
		case SWT.Dispose:
			if (DEBUG) {
				trace("handleMenu.Dispose", menu, menuModel);
			}
			cleanUp(menu);
			break;
		}
	}
	private void showMenu(final Event event, final Menu menu,
			final MMenu menuModel) {
		final IEclipseContext parentContext = modelService
				.getContainingContext(menuModel);
		final ArrayList<MMenuContribution> toContribute = new ArrayList<MMenuContribution>();
		final ArrayList<MMenuElement> menuContributionsToRemove = new ArrayList<MMenuElement>();
		ExpressionContext eContext = new ExpressionContext(parentContext);
		gatherMenuContributions(menuModel, menuModel.getElementId(),
				toContribute, eContext, false);
		addMenuContributions(menuModel, toContribute, menuContributionsToRemove);
		
		pendingCleanup.put(menu, new Runnable() {
			public void run() {
				if (!menu.isDisposed()) {
					unrender(menuModel);
				}
				removeMenuContributions(menuModel, menuContributionsToRemove);
			}
		});
		render(menu, menuModel);
	}