I'm currently running Fedora 23 with:
When I move the mouse cursor to the top bar (where the clock and system icons reside) the mouse cursor disappears. Also, if I hit the Mod/Windows key to bring up the activities/overlay display, the mouse disappears there. The cursor appears just fine when it sits on top of any other part of the screen (bare desktop, applications, terminal, etc).
I am on a Broadwell i7 laptop and I have tried various Intel acceleration options (sna, uxa, and glamor) as well as various Linux kernels (4.2, 4.3, 4.4). None of those affect the issue at all.
This *seems* to be very related to an upstream bug here:
Is there any way I can gather more detailed logs about what's happening as I roll the mouse onto the top bar? Thanks!
*** This bug has been marked as a duplicate of bug 1316010 ***