Introversion

I just finished the campagin when this (I think its a bug) bug came: Doors are open all the time. You know in a prison its not so cool, if your prisoners can go where ever they want to. They can walk straight out of jail! It sounds funny but makes the game unplayable ^^
Can anyone help?

You say you finished the campaign, so I take it you're now playing a new sandbox game yes? Do you have prisoners in your jail already? The doors will stay open until you get your first inmates to make it easier for your workmen to get around.