A coworker has been working for several days creating an Excel template which contains several tabs which have various drop-down menus in cells created using Data Validation. He suddenly lost all the drop-down widgets (the little arrow symbols) on one of the tabs. The data validation is still in place. If he types in a value not on the validation list he gets the error usualy error message. The widgets are missing from all of the cells on that sheet that contained drop-downs, but still appear on cells on other sheets where there are drop-down data validation. Clearing data validation and recreating it doesn't help. Any new drop-downs created on that sheet act the same (data validation in place but no drop-down lists).

I'm at a lose as to what might have caused this and how to fix it. Any suggestions? We much prefer to avoid having to recreate the sheet which would take the better part of a day!

Thanks!