let combo_box = |
#selected: &[string, null] = &null,
#on_select: fn(s: string) -> Any = |_| null,
#placeholder: &string = &"Type to search...",
#width: &Length = &`Fill,
#disabled: &bool = &false,
options: &Array<string>
| -> Widget `ComboBox({ on_select: &on_select, options, selected, placeholder, width, disabled })