works well, but If I had the choice of options I'd like to the newly opened tabs to open at the right of the last tab, not at the left (beginning) of the tab bar. The previous version I used on a older Firefox/Pale Moon browser did just this.

It works ,But found that on Facebook, that it stops friends pages from scrolling beyond a couple of pages.
After disabling it pages scrolled correctly
Doesn't effect my own page, strange. I can duplicate it