screen in its 4.0.2 version prevents users from kill -STOP'ing programs running under screen. Say you're running something network-intensive and want to temporarily pause it before you go to someone's house, and continue it when you return, you can't do this in the current version of screen.

Apply this patch to 4.0.2 and put "sigstop_restart off" in your screenrc. Then you can kill -STOP processes as you see fit.