Hover-expanding buttons in the menu bar are wonky on Firefox

[texodus]

Bug Report

Steps to Reproduce:

1. Hover over the "Theme" button, click the dropdown but then click away (lose focus) without selecting a theme.
2. Try to select a theme again

Expected Result:

The them should change

Actual Result:

Carnage. It looks like sometimes, the container element loses hover/focus state when the dropdown is open, causing the container to collapse and break the dropdown. This is certainly a Firefox bug, as it can only be triggered by collapsing the container when the dropdown is in an open state.

Environment:

Firefox

[texodus]

Thanks for the report. I've consolidated this and other Firefox issues into #2693, closing.