code: func (d *DropDown) AddOption(text string, selected func()) *DropDown {
  	d.options = append(d.options, &dropDownOption{Text: text, Selected: selected})
  	d.list.AddItem(text, "", 0, nil)
  	return d
  }
docs: // AddOption adds a new selectable option to this drop-down. The "selected"
  // callback is called when this option was selected. It may be nil.