It does what it says, and very well.
It would be even better if it did not require dangerous permissions (access your data for all websites)

This plugin is an essential in my toolbox. (Auto-highlight all, amazing for code reading.) With Firefox 75, it's back to working perfectly. Unfortunately had to survive for a few Firefox versions without it due to components in the browser breaking. Many thanks to the addon's author/maintainer for keeping this plugin going. He was a pleasure to interact with when I inquired about this now-past issue.

Very nice idea and implementation of virtual scrollbar is outstanding.
NOTE:
Native highlighting is not working due to FF bug.
If anyone has Ctrl+F8 shortcut occupied, FF support shortcut changing in extensions settings.
@Jerome
Is it possible to implement search function(e.g. from toolbar, or preferably from context menu)? It would be highly useful. No other extension provide similar features.

This is maybe the single most useful extension after a password manager. I read and write lots of technical text, and it really helps to keep an overview of the terms used throughout a page. Also good for spotting typos/variations of words not in dictionaries.

One Caveat: Native Mode does not work!

Great addon, thanks a lot! Can you add a hotkey to switch to the next found word? Also will be great to add ability to scroll the mouse wheel above search markers to view next founded word or press some button with mouse wheel scroll.

Oke sangat bermanfaat

please fix this, HighlightAll not working after update firefox , when i select word there is no Highlight for the same words in page
thanks for this great helpfull addons

Man, I love this thing. I so used to such functionality in IDEs that I added it to browser too. And now moving from chrome to firefox, this was the first extension I searched ( even before adblock). Your version does the job flawlessly and has good enough customisation

Useful and easy to use.

Great tool I used

This add-on made paper reading so easy for me!!

Merci au dev pour cette indispensable extension

Excellent Add-on. Must have.
Very useful improvement — to have a shortcut to un-highlight all. Currently it's only page refresh.
Possible improvement — when multiple colours are set, every new selection gets automatically the next colour.

Very handy. The one thing I didn't like about Firefox's Find feature was that it doesn't show the occurrences on the side scrollbar like Chrome does, which makes it hard to actually find where the matches are. This addon provides that, and in my opinion this feature should be in Firefox itself.

Нужное и удобное дополнение разработали!