I'm also having this issue suddenly. I've updated to the latest version of TreeStyle Tab (3.9.21) and Firefox Version 115.7.0esr (64 bit).

See recent reviews and possibly revert to a previous version until this is fixed by its creator.

• https://addons.mozilla.org/en-US/firefox/addon/tree-style-tab/reviews/

I have downgraded, but now I lost all my extensions, I had tons of extensions, how can I restore it?

What do you mean with downgrading? Did you download the Tree style tab extension or did you downgrade Firefox as the latter isn't recommended?

> cor-el Moderator > possibly revert to a previous version until this is fixed > did you downgrade Firefox as the latter isn't recommended?

@MAE, I also didn't know you could downgrade the extension. https://github.com/piroor/treestyletab/issues/3440#issuecomment-1917073672 is an explanation how to revert, worked for me 😁

   Uninstall TST
   https://addons.mozilla.org/en-US/firefox/addon/tree-style-tab/versions/ click "Download file" link for 3.9.20
   Add to Firefox
   Click "Manage extension" for TST and turn off "allow automatic updates"

A version Version 3.9.22 has been released to address this issue, so you can update to this new version. Apparently this issue happened when the bookmarks permission is disabled.

• https://addons.mozilla.org/en-US/firefox/addon/tree-style-tab/

The issue seems to have been fixed.