code: func ActivateControl(parent, control Control) bool {
  	DeactivateControls(parent)
  	res := false
  	ctrl := FindChild(parent, control)
  	if ctrl != nil {
  		res = true
  		if !ctrl.Active() {
  			ctrl.ProcessEvent(Event{Type: EventActivate, X: 1})
  			ctrl.SetActive(true)
  		}
  	}
  
  	return res
  }
docs: // ActivateControl makes control active and disables all other children of
  // the parent. Returns true if control was found and activated