User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/117.0

Steps to reproduce:

I can't reproduce it reliable, here is what I do when it happens:

1. Try to open a file (ctrl+O or File->Open File)
2. Window shows up, but I can't neither close it nor choose any file there
3. When I use shortcut I see ever growing o's being added to address bar. The same can happen with Crtl+S

Expected results:

It shouldn't hang.

I understand that this is not enough. Please let me know whether I should enable more logging / collection of debug info / grab other useful information.

The Bugbug bot thinks this bug should belong to the 'Core::Networking' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

This bug seems more related to Firefox UI.

I couldn't manage to reproduce this issue on my end, I tried on Ubuntu 20.04 x64.
Could you please try if the issue occurs in safe mode. Here is a link that can help you do that: 
https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode

Yes, it does repro in safe mode. Actually, I just found out that it does not hang, but it just opens enormous amount of "Open File" dialog windows - 50 or more. Does not happen with other apps (tried Intellij, evince, and GNOME terminal)

Can you please attach about:support page?
Thanks.

I can't add an attachment, please check download about:support content from https://drive.google.com/file/d/1eCLUsplFtCTtiPMyJ1TArjcXB9Avl6js/view?usp=sharing.

Looks like Snap issue then.