I tried this in TamperMonkey on Chrome. I got strange black blobs above the buttons with dropdown menus (the h# and the pin icon).

Otherwise it seemed to be working after some simple testing.

Re: @joeytwiddle:
Confirmed. Github recently updated their site design (minor tweaks) which resulted in those black blobs.
I've already fixed this issue locally. Still working on fixing another issue that maybe related to your other issue.
Will update soon.

Re: @joeytwiddle:
Finally got the time to fix and thoroughly test this issue after Github recently updated their site. Thanks for reporting.

Re: @jerone:

I just noticed they had disappeared, so came here to say ... Great job, thanks! :D