It is possible to reference a decision variable cell formatted as a date (such as 2/19/1900) and enter a constraint as follows in the OptQuest wizard's Constraints panel:
If you do this, OptQuest interprets it as 2 divided by 19 divided by 1900 and does not display an error message.
This behavior is consistent with that of the Microsoft Excel formula bar. For best results, use the Microsoft Excel DATE() function.