Generally, the answer is resize the field larger, but does not always work.
You can create a second copy of a field (or duplicate it) on a layout and play with it.
Backing your working databases on a regular basis is a good idea.
Ok. I found out that my report form field reverted back to a regular edit box. I had to change it to checkbox set and associate it with my value list. Adjust for visual horizontal display and it's all good.