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.model.workbench/src/org/eclipse/e4/ui/model/application/ui/impl/CoreExpressionImpl.java
* @see #getCoreExpressionId()
	 * @generated
	 * @ordered
	 */
	protected static final String CORE_EXPRESSION_ID_EDEFAULT = ""; 
	/**
	 * The cached value of the '{@link #getCoreExpressionId() <em>Core Expression Id</em>}' attribute.
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @see #getCoreExpressionId()
	 * @generated
	 * @ordered
	 */
	protected String coreExpressionId = CORE_EXPRESSION_ID_EDEFAULT;
	/**
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 */
	protected CoreExpressionImpl() {
		super();
	}
	/**
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 */
	@Override
	protected EClass eStaticClass() {
		return UiPackageImpl.Literals.CORE_EXPRESSION;