Grigore,

What version of VFP are you using?

>I was unable to close it: clear all, release all, no luck. I don't use references in those two forms.

A datasession can not close while an object instantiated inside it still exists. It's possible that the assign method is leaving an internal dangling reference that you can't do anything about.

Try taking your opg Enabled_assign code and moving it to a custom method, then call that method from your checkbox code and see if that fixes it.

>In the interactivechage of that checkbox I put some control enabled .T. of .F., depending the checkbox's value. I commented the code. Suprise. Datasession is released correctly. Uncomment the code, line by line. Found the problem:
>
>

>Thisform.Pgf.PagDataAcces.opgUpdateType.Enabled = .T.
>

>
>I double-checked this. That's the line. opgUpdateType is an optiongroup with two optionbuttons.
>
>In my optiongroup class I wrote a enabled_assign method which looks like this: