I can confirm it on Ubuntu 18.04, Firefox 67.0.4, NVidia video drivers, with any theme.
Interestingly enough, the corners are shown correctly when I start Firefox from a Slack link. I tried to use the same command line used by Slack to launch a link (which is just: firefox https://....), but that doesn't do the trick.
I can confirm it on Ubuntu 18.04, Firefox 67.0.4, NVidia video drivers, with any theme.
Interestingly enough, the corners are shown correctly when I start Firefox from a Slack link. I tried to use the same command line used by Slack to launch a link (which is just: firefox https://....), but that doesn't do the trick.