[RP] window flickery

[sabetts]

I've committed changes that should get rid of the window flickering when 
switching between transient windows. The classic example is in netscape when 
searching for a string that is not found. As I recall, it brought slower 
machines to their knees. Let me know if you get get any nasty behavior (I had a 
segfault after restarting but I was unable to replicate it).

I've also fixed a minor transient window and split screen bug.