I'm encountering a frustrating problem relating to data validation, and I'm
sure there's a simple answer.

On one sheet only, when I set up Data Validation (sourcing a list), the
little dropdown arrow to the side of the cell doesn't appear.

On all other sheets, the dropdown appears.

On the problem sheet, the validation still works (ie, I can't enter a value
that isn't on the list), but the dropdown doesn't appear.

Any ideas?

Thanks in advance.
Daniel