Rated 4 out of 5 stars

This is one of the very few highlighters that are not abandoned ages ago...
Restartless, multicolor, local/secure saving -- all the essentials are there. Thank you!!

I confirm the highlight persistence problem -- highlights made via the button are lost. BUT, if you make the highlight via context menu, they ARE remembered.

Other bugs:
-- When the selection contains any html element (even < br > or < i >), the start of highlight jumps to the beginning of the paragraph even though I only select from the middle of a sentence on.
-- The Undo most recent, and Erase all highlights -- just don't work.

I wanted to put 5 stars for encouragement but since I can't erase the highlight even after hard refresh, I'm stuck with pages that look like student textbooks... PLEASE fix this asap

And a feature request (if possible at all under Fx) : make a button to toggle a 'highlight tool' on and off, much like the MS Word highlighter, so you can create several highlights just by selecting text here and there, without clicking the 'A' button for each selection. Maybe it's doable by injecting JS to automatically highlight every time a selection is made, and a boolean to toggle the JS.

This review is for a previous version of the add-on (initial.rev674.1-signed.1-signed). 

Highlights made via the button should be remembered starting with rev748, which should clear preliminary review any day now.

Undo and erase seem to work for me, at least most of the time, but there's probably a bug in there somewhere, and finding it is next order of business.

Your feature request is right behind Nick2222's (making all features available through right-mouse menus), partly because of first come first served, and partly because I don't yet know whether there is an event that detects selections.