We wrote about how this extension makes firefox unresponsive, though it kind of is our fault for having 20 000 tabs open.

The developer responded -immediately- with a fix which we really appreciate and were surprised by. They told us to go to enable a performance setting in the general tab, that only considers active tabs.

However, the fix didn't work. It made firefox a little more responsive, but in that we only had to wait one minute per interaction with the browser instead of three.