Open
Description
The problem is that unselected messages have a background color like rgba(..., 0.9), which causes us to draw over the solid white background. This results in a drop to ~30 FPS on full screen Retina.
I think it would be possible to detect this case by computing the set of regions that are known to be entirely a solid color and promote transparent objects to opaque. Alternately, we could segment into tiles somehow. All of this would have to be done in a way that doesn't regress CPU time, of course.