Hi,

I am using data validation formulas under the "custom" drop-down" heading to
control the allowed input into a given cell. However, I also wanted to
include in the expression a constraint that would not allow an entry until
the previous cell had been filled as well. It seems that when I add
"NOT(ISBLANK(B3))", "ISTEXT(B3))" or any other entry to my formula
controlling C3, i.e.
"=AND(ISTEXT(B3),C3=DATE(2008,1,1),C3<=DATE(2012, 12,31))", the formula
stops activating the Error Alert and allows me to enter anything I want.
Any thoughts on why the formula would stop performing once I reference a
cell other than the one I am making an entry in?

Thanks in advance for the help,

Brian