Firefox - Get "Highlight all" button to be on by default

Solution 1:

You could try the latest version 1.3.4 of FindBar Tweak. https://addons.mozilla.org/en-US/firefox/addon/findbar-tweak/versions/

The "Highlight All" checkbox can be found in the extension's "Highlight" preferences panel.

Solution 2:

Starting at Firefox 50 you can change the default value in the settings.

1. Type about:config in the browser's address bar and hit enter.
2. Confirm you will be careful if the warning prompt appears.
3. The parameter findbar.highlightAll determines whether highlight all is enabled or not when you search in Firefox.

Source: http://www.ghacks.net/2016/06/11/firefox-page-search-improvements/

Solution 3:

You don't need any extension nor to go to about:config.

Since Firefox 54, just do a search (ctrl+f) and enable highlight all (alt+a). It will remember that automatically on future searches.

It is not necessary anymore to enable it through about:config

(please, upvote so more people can know it)

Solution 4:

The extension Highlight all will highlight all occurrences of a work by double clicking on a word. I don't know if that will help you with what you want.

I couldn't find a way of toggling the highlight all button in about:config, but the case-senstive toggle is listed there, so it's probably not directly configurable.