如何在Eclipse 4 RCP应用程序中禁用动态菜单贡献父级

public class DisableParentMenuContributionHandler extends AbstractHandler {

   @Override
   public Object execute(ExecutionEvent event) throws ExecutionException {
      // 执行菜单贡献的逻辑
      return null;
   }

   @Override
   public boolean isEnabled() {
      // 返回false来禁用菜单贡献
      return false;
   }
}

<extension point="org.eclipse.ui.menus">
   <menuContribution locationURI="menu:org.eclipse.ui.main.menu">
      <menu
         label="My Menu"
         id="com.example.mymenu">
         <command
            commandId="com.example.mycommand"
            label="My Command"
            style="push">
            <visibleWhen
               checkEnabled="false">
               <with
                  variable="activePartId">
                  <equals
                     value="org.eclipse.ui.editorss">
                  </equals>
               </with>
            </visibleWhen>
         </command>
      </menu>
   </menuContribution>
</extension>

<extension point="org.eclipse.ui.handlers">
   <handler
      commandId="com.example.mycommand"
      class="com.example.DisableParentMenuContributionHandler">
   </handler>
</extension>