I just ran into this again and thought I would post a message about it for future users of the system and message board. This happens from time to time when funds are being applied.
Today, we got $26k caught in the bucket and the only way to remove it was to go into the ar_session table and delete the entry. We clicked the trash can but nothing. It put 0.00 in the box but when the screen was closed and reopened. The funds where still there.
I looked at the javascript that is attached to the button. My question is that when the trash can is selected and the amount is set to 0.00. Should the recalculate button be selected after that to save the information into the database to clear it?
I can see in the new_payment.php file where there is a query to set the global amount to some value if the global_amount is yes.