For those who are looking for a solution for double-left-clicking:
There is a extension called Tab Tweak which supports double-left-clicking close tab in Firefox Quantum, this extension is especially for Chinese Edition Firefox so you might find it difficult to get it from Mozilla's extension library. However, it is available at Firefox China Forum: http://mozilla.com.cn/forum.php?mod=viewthread&tid=319507&highlight=%E6%A0%87%E7%AD%BE%E9%A1%B5%E4%BC%98%E5%8C%96
Click the green button then it will be installed.
I am using Firefox Quantum 57.0 and it works perfectly.
Thank you :-) Apparently, some users are looking for an extension like the one you mentioned. That works on Firefox 57. But, I'm not sure if add-ons/extensions with that architecture would continue to remain supported.
It seems most of the people are not reading the description before trying to use this extension. And hence not understanding that this extension is meant as a replacement for "Rights to Close" legacy extension ;-)
It works incredibly well but causes some issues with various sites such as Facebook. Most notable symptom is dialog boxes where comments would go do not show up. I have tried it with and without the Stylus plugin. Turning Double Right Click plugin off and reloading the Facebook page seems to resolve the problem but I really, really want this feature.
If I can provide any assistance on troubleshooting it let me know. It's an excellent add on!
Actually works. But need to click on the page, not on the tab. Nice. Leave the contextual menu open since you are using the right button. But no biggy. Anyway, it's better using the right button than the left one.
Thanks for the feedback, I guess you might have double right clicked on the tab header or tried to use it on a native page or the Mozilla add-ons site itself (it doesn't work for those cases due to security/architecture reasons).
This extension closes the active tab when you double right click anywhere on the page.