How to fix a bug on Firefox with select?

Question

css

Select should appear when hovering over the block. when you open select and hover over one of the options, the options immediately disappear. This problem was found in Firefox, in Chrome everything works fine. How to fix?
https://plnkr.co/edit/z2uW4O6D1uLFnsoLjWeb?p=preview

Answer 1

Apparently in FF, hover disappears when hovering over select items from the block. Perhaps the output will be tied somehow to focus on the select. CSS focus-within may help or scripts, when focusing on a select, add a class for the block through which the select will also be visible similarly to the hover