Bug 188911 [Contributions] [Doc] IContributionItem.dispose() says it should not be called by clients
3.3 RC1. IContributionItem.dispose() says it should not be called by clients but this happens all over the place in the SDK e.g. to dispose menu managers which are also an IContributionItem. I guess this restriction should be removed.
bundles/org.eclipse.jface/src/org/eclipse/jface/action/IContributionItem.java
*  <code>false</code> for normal items
     *
     * @see GroupMarker
     * @see IContributionManager#appendToGroup(String, IContributionItem)
     * @see IContributionManager#prependToGroup(String, IContributionItem)
     */
    public boolean isGroupMarker();
    /**
     * Returns whether this contribution item is a separator.
     * This information is used to enable hiding of unnecessary separators.
     *
     * @return <code>true</code> if this item is a separator, and
     *  <code>false</code> for normal items
     * @see Separator
     */
    public boolean isSeparator();
    /**
     * Returns whether this contribution item is visibile within its manager.
     *
     * @return <code>true</code> if this item is visible, and
     *  <code>false</code> otherwise
     */
    public boolean isVisible();
    /**
     * Saves any state information of the control(s) owned by this contribution item.
     * The contribution manager calls this method before disposing of the controls.
     * 
     * @since 3.0
     */
    public void saveWidgetState();