It can be very simply reproduced with the xevent program as described in the ubuntu bug report. I filled this bug for the xorg intel driver component, instead of libXtst, because it seems to me specific to the intel driver. I could not reproduce it on another rawhide box, with the radeon driver.
With current rawhide, I experience the same problem than the one described here:
https:/ /bugs.launchpad .net/ubuntu/ +source/ libxtst/ +bug/337926
It can be very simply reproduced with the xevent program as described in the ubuntu bug report. I filled this bug for the xorg intel driver component, instead of libXtst, because it seems to me specific to the intel driver. I could not reproduce it on another rawhide box, with the radeon driver.