This one has been driving me crazy for ages...
When I use the Browser Toolbox - with the option Disable popup auto-hidebeing checked - and I hover over or select an element in the inspector , the info panels/tooltips that are usually displayed above and/or in front of the targeted/selected elements are covered by the open popups.
Also, the selected UI popup parts are not highlighted as they would be for other bits, there's only that dotted grid visible - again partially hidden - that gives you a general idea of what you are looking at.
This is on MacOs/Fx 115esr; I understand the issue is the same on Windows.
I've tried lots of css and javascript codes to find a way to target that thing, but to no avail.
The Fx popups in general have a silly high z-index, so that might be part of the issue; I'm wondering if there's any way to fix that.
Screenshot below.
I can't remember of the top of my head, but I seem to recall the custom highlighter is inserted to the end of the dom in targeted window, so maybe you can find it just from the inspector.
But I don't think it will do you much good because it sounds like you would need to modify native c++ code to make the changes that would allow the current highlighter implementation to work with panel or popups. At least, that's how I understand it.
Thanks again; I kinda managed to target the highlighters' css with force by js, but it's getting too much trouble at this point.