code: func (l *ListBox) FindItem(text string, caseSensitive bool) int {
  	for idx, itm := range l.items {
  		if itm == text || (caseSensitive && strings.EqualFold(itm, text)) {
  			return idx
  		}
  	}
  
  	return -1
  }
docs: // FindItem looks for an item in list which text equals
  // to text, by default the search is casesensitive.
  // Returns item number in item list or -1 if nothing is found.