val ok : [> `OK ] buttonsval close : [> `CLOSE ] buttonsval yes_no : [> `YES | `NO ] buttonsval ok_cancel : [> `OK | `CANCEL ] buttons
type color_selection = [ | `OK |
| `CANCEL |
| `HELP |
| `DELETE_EVENT |
]type file_selection = [ | `OK |
| `CANCEL |
| `HELP |
| `DELETE_EVENT |
]type font_selection = [ | `OK |
| `CANCEL |
| `APPLY |
| `DELETE_EVENT |
]type about = [ | `CANCEL |
| `CLOSE |
| `DELETE_EVENT |
]