Firefox will not open local files in new tab after 20.04 update

[Coburn Ingram]

Mentioning this issue here to see if it triggers any ideas.

I am using Hirsute and installing updates daily. In the last few days I
noticed that when I try to open a local HTML file from Nautilus it triggers
a "Firefox is already open" popup. This also happens when I try to launch
an app served through Tomcat from the taskbar. If Firefox is already open
it will not open the page. Apps do open from bookmarks, however.

Things I have tried:

1) Delete new add-ons
2) Refresh my profile
3) Allow global launching of local files in about:config (don't remember
the name of the setting but it has been reverted: see below)
4) Purge and reinstall the Tomcat app in question (I had dirty-installed
it). This is irrelevant because the problem also applies to plain HTML files
5) Delete lock files in .mozilla (worked one time only)
6) Purge and reinstall Firefox

Short of reinstalling the OS, I am not sure what else I can do. I have
basically done all that Mozilla suggests for fixing this problem and it did
not work. Could it be a problem with Ubuntu or Gnome?

Thanks,

Coby
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