I just installed one of those 6 panel masonite doors. It was not prehung so I had to install new jambs, stops, hinges. The door is flush on the hinge side but on the knob side the top of the door sticks out a little too much. I'm thinking of bracing a piece of wood across the top corner and leave it in place for sometime and hope that it starts to go back. Anybody have a better way?
I guess the door was probably warped when I bought it, didn't think to check it.