In Data Validation List (2007) in one workbook only: In cell dropdown not showing?!

I have the checkbox for in cell dropdown checked (in data validation)
There are multiple sheets that have data validation lists in this workbook - none of them show the dropdown. If you try to input wrong info - you get the error.
I have another workbook that has data validation - working like a charm.

There has to be some setting for this workbook that I inadvertantly turned on or off.

Does this sound familiar to anybody?