Hello, I thought I had already raised this issue, but I can't see any emails. So maybe mistaken. But anyway, the problem is when I click on a pull down menu - any pull down menu - in Firefox, it previously appears, but then disappears immediately. e.g. right click on a web page (any web page). On click on the one of the Firefox plugin menus. Or the Firefox menu. Unlikely many of the reported similar problems restarting Firefox solves the problem, and it doesn't appear to be a problem with my Profile. As in I have completely rebuilt my profile from scratch several times, and eventually the problem comes back. Rather, I have found what triggers it appears to be clicking on a link within notmuch inside emacs. The page loads OK. Then the very next menu fails however. It only happens if I open a page from emacs. If I manually run "firefox-esr http://www.google.com/" or "xdg-open http://www.google.com/" it works fine. This has happened a while now on a range of different computers, running different profiles, on different versions of Debian. Just noticed running strace on the emacs process, the firefox invocation is a bit more complex then I might have noticed. I don't see any URL even on the command line. Wonder if there is something here that is killing menus. [pid 16180] execve("/usr/lib/firefox-esr/firefox-esr", ["/usr/lib/firefox-esr/firefox-esr", "-contentproc", "-childID", "13", "-isForBrowser", "-prefsLen", "7297", "-prefMapSize", "185946", "-parentBuildID", "20200720181548", "-greomni", "/usr/lib/firefox-esr/omni.ja", "-appomni", "/usr/lib/firefox-esr/browser/omni.ja", "-appdir", "/usr/lib/firefox-esr/browser", "11615", "true", "tab"], 0x7fe29880c900 /* 54 vars */) = 0 -- Brian May <brian@linuxpenguins.xyz> https://linuxpenguins.xyz/brian/