Reproducible: always

Steps to reproduce:

1. Bookmarks menu open
2. Mouse hover on an bookmarks so that it will be highlighted
3. Right click on a bookmark so that places contextmenu will popup
4. Move mouse on to the context menu

Actual Results:
highlight disappears
See screencast https://youtu.be/6nSNNW__Qlk

Expected Results:
highlight should keep until mouse move to another menuitem

I'm trying to reproduce on Windows 10 with Nightly, I can if I move the mouse slowly the selection starts flickering, quite annoying especially in case of epilepsy.

Can you tell whether this is a recent regression?

This is not resent regression.

Regression window:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=e9c5611100b7&tochange=094a7967e171

As soon as the status label fades out, the highlight of the context menuitem seems to disappear.

thank you! if it's not recent and we didn't listen about it until now, it's likely not a major annoyance. it would still be nice to fix it.

The platform list currently says Windows, but it's occurring in at least 2 version of MacOS too. Don't know about Linux.

Happens on both Catalina 10.15.7 and High Sierra 10.13.6

At least on Catalina 10.15.7, this only happens for me with folders that have many bookmarks in them. Right click on one of them, and can't select any context item with the mouse, such as Open in a New Tab or Delete. If the folder has few items, then it works. By the way, you CAN select context items by using the keyboard.

On Windows 11, we were able to repro the bookmark selection itself flickering.
We should also check whether this issue also affects native context menus.