I also ran into this bug recently and reported it on Bugzilla — it's very rare I have enough windows open simultaneously to run into issues like this, so any contributions over there would be much appreciated.
I understand that supporting OS features can limit other functions, but this is really baffling prioritization. Keeping track of many windows via the menu is now needlessly difficult and extremely confusing. What's the point of a list that changes or...
Good mock-up design! Now that we can manage and remove extensions right from the menu instead of needing the add-on manager, I think they should also allow enabling and disabling extensions directly from the menu. Being able to pin specific extension...