Create an option for Dashboard Filter field to be read-only

1) What is the problem or goal the end user is trying to solve or accomplish?

Admin is trying to prevent users from using/entering a value that is not in the filter dropdown. At the moment, the field is a combobox. Therefore, users are able to fill in any value, which caused the dashboard to not display any result.

2) How are they solving it currently?

No workaround.

3) What is the recommended solution by the Customer?

Create an option to make the Filter to be read-only to limit the option for Dashboard Filters.