Comment 5 for bug 1256702

Mir team came to the conclusion last week that we would all like to see something from design to better describe the exact requirements. Because we're concerned that you might (unlikely but might) be requesting things you don't need in the end.

Essentially, our only requirement for accepting this feature is to ensure session surfaces do _not_ have alpha channels after the login. Or ever just to ensure that user sessions don't ever have alpha channels. So if it's just the greeter then that's probably cool.

Yes, my concern is around bypass and occlusion optimizations. Both of those are instantly disabled by having a translucent surface on top. Which is fine if it's only the greeter.