code: func FindChild(parent, control Control) Control {
  	var res Control
  
  	if parent == control {
  		return parent
  	}
  
  	for _, ctrl := range parent.Children() {
  		if ctrl == control {
  			res = ctrl
  			break
  		}
  
  		res = FindChild(ctrl, control)
  		if res != nil {
  			break
  		}
  	}
  
  	return res
  }
docs: // FindChild returns control if it is a child of the parent and nil otherwise