Further to that, I like the idea of a "low security" window system, where any app can potentially poke pixels to the entire screen but is "advised" to draw within a certain rectangle. This could benefit performance. Also, if a window is partly obscured such that its drawable area would not be a simple rectangle, I'm happy for it to stop updating until it's on top again. Seriously, who cares about animating obscured windows? It's not worth the bother to implement that.
For >99% of the programs I run, I have to trust them and assume they are well behaved. And I am not concerned that the code might be malicious. Sam > I don't love X11 ... rio ... on ... Linux
