We should make sure that we're not drawing more than necessary in composting layers because of rect coalescing.
Created attachment 129370 [details]
Comment on attachment 129370 [details]
In drawRect: we examine the total area of all texts and do a single paint if they cover a sufficiently large fraction of the clip bounds. I wonder if we don't need something similar here.
I wonder that too. I'll look to see if CA does that already.
This change was made to help http://ie.microsoft.com/testdrive/performance/mazesolver/default.html performance.