[fw-general] checkbox does not work anymore?

[Bart McLeod]

my checkboxes remain checked, whatever I do... They worked fine, but no 
longer...

Any help appreciated. I use '0' and '1'  as values. Months ago they 
worked like magic: without any explicit setting. Weeks ago I had to 
explicitly set them, now they remain set no matter what I do to them. I 
feel really stupid now.

Bart