Slightly off-topic, but does anyone use a Vim plugin for Firefox? I keep trying to switch, but the scrolling of VimFX drives me crazy. Here's an issue outlining the behavior: https://github.com/akhodakivskiy/VimFx/issues/830
Are there any other Vim plugins without this issue?
Vimium-FF <https://addons.mozilla.org/en-US/firefox/addon/vimium-ff/> is the only Vim-keyboard-binding plugin I know that will work with Firefox 57 and above. I haven't noticed any scroll jankiness as you describe, but it's possible I have my key-repeat-delay set low enough that it doesn't affect me.
I'm still using Pentadactyl, which is incredible, but it's almost certainly doomed. You'll need to use the signed version on github: https://github.com/willsALMANJ/pentadactyl-signed You might consider Vimperator, which is similar, but inferior iny opinion. It has better support, though, and is more likely to survive into the future.
If you're looking for something simple, VimFX works, but it's too basic for me. Not sure of the future of VimFX.
Can't say it has ever bothered me, but the future of Vim extensions on Firefox once XUL in extensions is phased out for good is dire. Right now, there is a port of Vimium (which I suspect gets my FF 55 to hang). I don't think any of the other extensions are likely to make it.
Are there any other Vim plugins without this issue?