This is very probably https://bugzilla.mozilla.org/show_bug.cgi?id=1495900, which will be fixed in firefox 77, according to the upstream bug status.
** Bug watch added: Mozilla Bugzilla #1495900 https://bugzilla.mozilla.org/show_bug.cgi?id=1495900 ** Also affects: firefox via https://bugzilla.mozilla.org/show_bug.cgi?id=1495900 Importance: Unknown Status: Unknown -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1870827 Title: Firefox hangs after simultaneously opening Chrome/Electron-based applications To manage notifications about this bug go to: https://bugs.launchpad.net/firefox/+bug/1870827/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
