Works perfectly with Firefox 57.01 on Ubuntu 14.04.
Just think of doing the little manipulation before: Create the "Searches" folder in the bookmarks and assign the keywords to the search engines.
I am very happy. Thank you.

Fonctionne parfaitement avec Firefox 57.01 sur Ubuntu 14.04.
Il faut juste penser à faire la petite manipulation auparavant : Créer le dossier "Searches" dans les marque-pages et attribuer les mots-clés aux moteurs de recherche.
Merci beaucoup.

Just do its work! Very satisfied with.

Ne fonctionne pas. FF57.0.1 linux
Rechercher: example of words.....no motor choice

Enfin. Excellent. Et merci.

Great! Without too much effort I've got back most of the functionality of the now dead – due to Quantum's limited API – add-on that used to do this. In the end I think this bookmark method is actually easier than having to add to the installed search engines, which is one aspect of Firefox that Mozilla seem to have made unnecessarily complicated in recent years.

The only thing I would suggest is rather than adding a new 'search' item to the context menu, usurp the existing one so there aren't two. Would that be possible?

Takes a bit of work, but it works well after you do some configuration. Thank you!
If I can post a couple examples for your Searches folder, the two that I use most often:

https://www.startpage.com/do/dsearch?query=%s

http://www.imdb.com/find?s=all&q=%s

The %s is the wildcard that is replaced with whatever you have selected on the page you are searching.

Many searches are available this way.

It works. Thank you^-^

A bit awkward to use, but this is not the developer's fault. In an ideal world, it would directly use the already defined search engines in the browser, but the WebExtension API does not give access to that. This add-on offers a nice alternative.

Thank you for the great work!

Questo componente aggiuntivo combina la procedura di Add to Search Bar (RIP) con la ricerca contestuale. Ogni sito con un motore di ricerca interno può essere aggiunto alla propria lista di motori posizionando il cursore all'interno del campo di ricerca e selezionando 'Aggiungi una parola chiave per questa ricerca' dal menu contestuale. Si apre una finestra di dialogo che chiede il nome x il nuovo motore, una parola chiave e la cartella di destinazione, che deve essere preventivamente creata, con il nome Searches, nel Menu Segnalibri. Da provare!

It's works! Thanks

Stopped working today, but it worked yesterday. It fails at "glosbe.com"

Too complicated to get this work if it dose work.

Good idea! But not getting the search engines already installed is a failure. Bookmarking each search site is too much work to get it working.
I know, Iknow, it's a limitation of the webextensions API, but perhaps you/we should talk to Mozilla developers on how to make it work and correct/patch the API.

I added a "Searches" folder to bookmarks. Then highlighted a word. The extension's "Search for" line shows up in the context menu. BUT none of the search engines are displayed.

THANK YOU, THANK YOU, THANK YOU!

ps.
possible to move this under right position in context menu? under firefox's „search google „for””? seems like a right place

Just what I wanted to make. Perfect !
I already had a folder with keyword searches. It's like you're in my head :P

i forgot to rename my search's folder to Searches, duh. im sure the more i use it the more ill have some suggestions. for starters, would be nice if you could use the middle click to keep the highlighted word selected and the context menu open to continue to keep running searches and opening tabs using different search sites. this is something SmartSearches could do, so this is a bit of a downgrade switching to this addon but it sure beats not having anything.

Probably the best replacement for SmartSearch, but there is still room for improvement ;) For example: Is it possible to change the position of "Search for" in the context menu? I would like to have this option at the very top.

Not for windows :-(

Using bookmarks for search engines is more flexible and powerful.

Can you make an option to have search features popup on the page near the highlighted word?

It'll be much quicker to search and access the addon, instead of drilling down into the context menu.