* @return the action or <code>null</code> if the <code>index</code>'th
* {@link DockAction} is not a {@link CommonDockAction} (and hence no {@link CAction}
* can be found)
*/
public CAction getAction( int index ){
DockAction action = intern().getDockAction( index );
if( action instanceof CommonDockAction ){
return ((CommonDockAction)action).getAction();
}
return null;
}