Works wonderfully on Firefox 91 (July 2021). Great extension.

Doesn't seem to work (68.0.1)

All hail Mike Conley!

https://bugzilla.mozilla.org/show_bug.cgi?id=17754#c177

Thank you for a wonderful add-on.
I was troubled because tab submission could not be used with firefox 57.

There's a website I use where I frequently middle click the submit button to submit forms to new tabs, so this add-on is essential for that.

The main issue I encountered is that this was triggering the popup blocker in Firefox 57. I had to add the particular website to my popup whitelist to get middle clicking buttons working as desired.

Thanks for extension, it is so useful for me! And seems it works with Middle mouse click - opens new Firefox tab for submit. So please describe this in extension description