Created attachment 229031 [details] Repro See the attached repro. It's not possible to hit the controls.
Created attachment 229044 [details] Minimized repro A better repro
Created attachment 229050 [details] Another repro
Looks like we miss depth sorting information when we cross the boundary from region layer to flow thread layer.
Created attachment 229218 [details] Patch
Comment on attachment 229218 [details] Patch r=me
Created attachment 229266 [details] Patch for landing
Comment on attachment 229266 [details] Patch for landing Clearing flags on attachment: 229266 Committed r167215: <http://trac.webkit.org/changeset/167215>
All reviewed patches have been landed. Closing bug.