Ability to "select" a value that is not in the list

[fgeorges]

I am not 100% sure this is a feature request. I have not found a way to achieve this, in the entire doc, but I might have missed it.

Is your feature request related to a problem? Please describe.
The user needs a dropdown list with all known values to select from (95% of cases.) But the user also needs to be able, in rare occasions, to fill in a custom string.

As far as I know, it is either one or the other (constrained with a list of all choices, or free form input field with no help for common cases.)

Describe the solution you'd like
A select field, but with the ability to provide a string value that is not in the list. Kind of a mix between text and select-one.

In the screenshot below, the user should be able to type in Nah, fourth is with me and select it as the value of the field.

Describe alternatives you've considered
The alternative is to have two fields (a text and a select-one,) but this makes the form quite confusing for the user.

Screenshot
Example mentioned above: