Can I have the old version back ?
this new update (on july 6, 2020) is a lot slower and make text selection impossible on some pages, as it makes the highligh selection to show only after 2 to 3 seconds
--- update ---
Finally, after testing all combinations, it seems that it is a Firefox issue more than coming from this extention. I uninstalled all plugins/extensions and I still had the issue.
But it doesn't explain why it was working a day before while this was the only extension that had an update on the 7th of july.
Also, it doesn't explain why the "Owl" extension solves the issue when activated.