Bug 7235 [Contributions] Need dispose() for action delegates
bundles/org.eclipse.jface/src/org/eclipse/jface/action/IContributionItem.java
* @param index the index where the controls are inserted,
 *   or <code>-1</code> to insert at the end
 */
public void fill(ToolBar parent, int index);
/**
 * Returns the identifier of this contribution item.
 * The id is used for retrieving an item from its manager.
 *
 * @return the contribution item identifier, or <code>null</code>
 *   if none
 */
public String getId();
/**
 * Returns whether this contribution item is enabled.
 * 
 * @return <code>true</code> if this item is enabled
 */
public boolean isEnabled();
/**
 * Returns whether this contribution item is dirty. A dirty item will be
 * recreated when the action bar is updated.
 * 
 * @return <code>true</code> if this item is dirty
 */
public boolean isDirty();
/**
 * Returns whether this contribution item is dynamic. A dynamic contribution
 * item contributes items conditionally, dependent on some internal state.
 *
 * @return <code>true</code> if this item is dynamic, and