I've been using this for years in Windows and I'm very happy with the long left-click especially and making it change to the new tab immediately.
Since I changed to Linux (Mint Cinnamon) I notice a strange behaviour. When I return to the page I left the whole page background is "glued to the mouse pointer" and moves with it until I make a single click and normality is returned.
It's a small thing but a bit annoying.

It does not work for links from the home page of the Firefox. The rest is not bad.

Great extension, works just as described, although I would suggest adding support for opening links from the bookmark bar!

I think I solved the recent "not working" problem by checking the option "Enabled" (it was unchecked) and deleting the default "F2" Keyboard Shortcut. Now, long left clicks open links like they should and F2 does nothing to the add on. I tested with 0.5b12 on 78.10.1esr and across restarts. Thanks for this great add on!