A family of Microsoft relational database management systems designed for ease of use.
Hi, What Daniel, Ken and I are all suggesting is that you NOT pursue that plan for a drop down box based on a Multi-Value Field. In my 2 decades of experience with Access, I've made nearly every possible mistake, some more than once. One I will not repeat, though, is trying to use Multi-Value Fields in Access. It's a doughnut too many.
Ken's sample is a much more reliable way to proceed.
If you persist in going down the MVF path, of course, you'll gain a bit of experience that will serve you well in the future, but it'll come the hard way.