It turns out that the app object method that was trying to close the second form's database and set it back to the first one couldn't close it, even though I was setting the datasession to the form's datasession before trying to close it. I copied the method code without the datasession stuff to a method on the form that opened the second database and now the 'wrong' one is closed correctly. I'm not sure if the database is 'owned' by the form or the datasession, but this appears to indicate that it goes with the form.

Thanks to everyone for all the input!

Deri