Bug 7235 [Contributions] Need dispose() for action delegates
bundles/org.eclipse.jface/src/org/eclipse/jface/action/MenuManager.java
*   <code>false</code> if disabled
 */
public boolean isEnabled() {
	return true;
}
/* (non-Javadoc)
 * Method declared on IContributionItem.
 */
public boolean isGroupMarker() {
	return false;
}
/* (non-Javadoc)
 * Method declared on IContributionItem.
 */
public boolean isSeparator() {
	return false;
}
/* (non-Javadoc)
 * Method declared on IContributionItem.
 */
public boolean isSubstituteFor(IContributionItem item) {
	return this.equals(item);
}
/* (non-Javadoc)
 * Method declared on IContributionItem.
 */
public boolean isVisible() {
	return visible;
}
/**