Re: dynamic window calculation, can't detect null on category?

I don't use the string.format stuff because it becomes too hard to alter with lots of fields.

I will simplify it for troubleshooting.  The following works if I select a category, but the calculation fails when i change it back to null, by clearing selection.

import System
static def GetAttributeValue(Activity):    Value = ''    TermDateMand = false       if Activity.Category != null:        TermDateMand = true    Value = Value + ':SetMandatory(_DateEmpNotified,' + TermDateMand + ');'       return Value