Dynamic field display based on previous fields enum list selection matching a criteria (Text name)

I need to display a form field if the previous field matches one of the values in the enum list. So the enum list is 4 values one of which is construction. If the selected field prior is construction I want to show the next field called projects which is a list of projects from another table. I am getting errors with the showif settings because it is an list. Not sure how to work with variable or values not already written to a table yet?

Warum nicht einfach in Showif von Projekten den Ausdruck IsNotBlank([Konstruktion]) setzen.

Thanks, I reworked the design and used your advise. It worked. Thanks,