Cell Custom Validation

[eggyjla]

I'm having a problem with my cell validation. I either want the cell to be Blank or contain "x". I've selected <custom>, checked the ignore Blanks box and entered x for formula. After appying, the cell appears to work until any value is entered at which time the error window is displayed. What is wrong with this?

 

[The Todal]

Select "List" from the Allow options, then uncheck the In-cell dropdown box

 

[The Todal]

Select "List" from the Allow options, then uncheck the In-cell dropdown box. In the Source field put simply "x" (without quotes)