FireFox hides menu when hovering over select options

[JoryHogeveen]

Describe the bug

For some reason when using firefox it removes focus on the menu when hovering over the select dropdown which triggers WordPress core to hide the menu again.

Select options aren't really usual within the toolbar so I doubt WordPress core will fix this issue.

Reference: https://wordpress.org/support/topic/impossible-to-change-the-position-of-the-menu/

[JoryHogeveen]

Found the solution here: https://stackoverflow.com/a/811994/2539261
Apparently FireFox triggers the mouseleave event on the select element when moving to the select option. This triggers event bubbling and therefore triggers the WordPress toolbar script to hide the menu.