My colonists keep sneaking in to sit at the prisoner's private table to relax and forcing the prisoners to eat on the floor or playing chess in their room while they're trying to sleep. I try not to torture the prisoners that I'd like to keep.
look at the table you have built in the prison room, click on it, and look at the bottom of the screen, you can deselect that table as a rally point for your colonists.
I remember seeing somethign similar in the last version ...
my colonists would love it to get themselves a bottle of beer and then sit on the chair in one of the prisoners cells in order to drink it :D
Thanks for reporting. This is fixed now.