I mastered the show field for checkbox selection earlier today (thanks to Herb) using the contains function.  But need to ensure that when a user deselects a checkbox, the data is cleared from the field and the field hides again.

I have tried notContains later in the script, so the system checks if the checkbox is clear, but it causes errors.

I have also tried isnull, but cannot get this work.

Any help would be appreciated.

Thanks very much