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
if (DEBUG) {
				trace("cleanUp.run()", menu, null);
			}
			cleanUp.run();
		}
	}
	private boolean isVisible(MMenuContribution menuContribution,
			ExpressionContext eContext) {
		if (menuContribution.getVisibleWhen() == null) {
			return true;
		}
		MCoreExpression exp = (MCoreExpression) menuContribution
				.getVisibleWhen();
		ReferenceExpression ref = new ReferenceExpression(
				exp.getCoreExpressionId());
		try {
			return ref.evaluate(eContext) != EvaluationResult.FALSE;
		} catch (CoreException e) {
			e.printStackTrace();
		}
		return false;
	}
	public void dispose() {
		Menu[] keys = pendingCleanup.keySet().toArray(
				new Menu[pendingCleanup.size()]);
		for (Menu menu : keys) {
			cleanUp(menu);
		}
	}
}