I seem to be having some difficulty with what seems to be a pretty simple effort. I am trying to use a calculation that ready an object that was created as a copy of the object "System/YesNo". This is a reference list that has simply has an Listing for "Yes" and "No". I am trying to make a window calculation that looks at the selected value and makes another attribute mandatory is Yes is selected. I am getting an error each time I test this, but I am really not sure what I am doing wrong. I am hoping a second, third, fourth. etc. set of eyes can help me see my problem. Thank you in advance. Bellow is an image of my calculation so far and the error I am getting.