Called when user selects an item from a drop down menu.
    menuClick(id, menu_index, [event])
    
    
        | event | object, event object | 
    
 
Returns 
undefined.
Description
This method only works for toolbar item of type menu. It is called when user selects a menu item. It is used internally, but you can use
to emulate clicks. This method emits 
.onMenuClick event.
If you have toolbar defined in the following way:
You can emulate menu click in the following way: