Pointer can leak through the corners of a barrier box
Submitted by Pierre-Loup A. Griffais
Assigned to Xorg Project Team
Created attachment 85588 pointer barrier test case
See attached test-case; it creates a box of 4 pointer barriers from 50,50 to 500,500 on the root window. If you start it while your pointer is in there (or warp it in there yourself) you can easily move it out of the box by hugging one of the borders and wiggling it around a corner. I can do it trivially on 1.13.0, but Peter Hutterer and Jasper reported that they could also get it to happen (less trivially) on recent RCs / git snapshots.
Attachment 85588, "pointer barrier test case":