I've did an indepth investigation on this select dropdown problem and posted an issue at bugs.webkit.org: https://bugs.webkit.org/show_bug.cgi?id=238318
It's a problem with dropdowns of several components (such as select, input file/date/month) where either the animation to have the dropdown appear or disappear seems to get stuck. You can sometimes see the dropdown being tiny and very transparent (if you zoom into a screenshot) and sometimes you'll be able to select an option even though you don't see the dropdown.
Topic:
App & System Services
SubTopic:
Core OS
Tags: