Comment 6 for bug 1615871

(In reply to comment #3)
> Yes, but he also said that using WidthOfScreen is bad in any case

True. r=me on that basis, but I recommend giving the upstream bug a couple days to settle before committing, now that the Xorg folks are actively looking into the issue.

We also should have an answer to their question as to why we use an offscreen window instead of a pixmap, which is clearly their recommendation.