In the latest Firefox version(116.0.2 (64-bit)) the button "List all tabs" won't show any tabs unless I close like half of them, then it works again if I open new random tabs. Currently 246 open tabs.
Any other way to fix this? I don't really wanna close those tabs.
The way I know this is that I tested in a sandbox with the same profile to try to find the problem.
EDIT 14/Aug/2023: So I just found out the issue was some tabs that had a " --" at the end of the title probably caused by some addon made this issue happen. It probably isn't really a - but I don't know what character is that.
All you have to do is just copy the url, open a new tab, paste the url and go. Close the previous tab with " --" at the end.
Just make sure you are not opening a new tab with CTRL+(clicking the + icon) from the "broken" tab with the " --".
Example.
Hope this helps someone else.
Although i managed to fix the problem, I went back to test it and indeed it gave an error:
The fix is in the edit above.