for(var/obj/O in usr.client.screen)
del O

Problem description:
This simple line of code that deletes everything on the the users screen seems to not be working correctly. I have 2 elements on the screen that I want to take off, obj/NAVI and obj/Navi_Select, both of which aren't being taken off, or one is and not the other. I have lines of code beneath this one, but it doesn't go to them and the for-loop just stalls. Any ideas?

Maybe null the client.screen list?
Does this peice of code reside in a proc that belongs to either obj/NAVI or obj/Navi_Select?
In response to Elation
Never mind, I fixed it. I was deleting an object on the screen that was using the proc causing it to stall.

Thanks though. ^_^