Unable to scroll through characters list on Firefox

Not able to reproduce with the same version of Firefox on my Windows machine. Might be a Mac-specific issue.

Do you still have the problem when viewing the page in an incognito window (or private window in Firefox I guess)? Just to rule out any possibilities of extensions messing things up.

Looks like we just don't support the fallback case for MacOS (all browsers on MacOS can't use custom scrollbars).

Will look into getting this fixed up, thanks for your help!