code: func (menu *Menu) Popup(w *window.Window) {
  	go func() {
  		for {
  			if w.TargetID != 0 {
  				command := Command{
  					Method: "popup",
  					Args: CommandArguments{
  						WindowID: w.TargetID,
  					},
  				}
  
  				// Thread to wait for Stable Menu State
  				menu.CallWhenTreeStable(&command)
  				return
  			}
  			time.Sleep(time.Microsecond * 10)
  		}
  
  	}()
  }
docs: /*
  Popup creates a popup menu on the given window
  */