Firefox browser’s Find bar, which lets you search for words and phrases on a page, to get three changes: the find toolbar includes an option to search for whole words only, and it highlights every instance of the search phrase you’ve entered by default, instead of you without the need to click on Highlight All button, and it also dims the page as well.
Mozilla internally calls better highlighting and page dimming as modal highlighting feature, you can observe this behavior of Find bar for page searches in Safari and Opera 12.x browsers also. If you want to disable the new changes added to Find bar, you can, follow the steps mentioned below for that.
READ: How to Make Find bar in Firefox to Hide Automatically while Changing between Tabs
Disabling Firefox Find bar’s page dimming and highlight all features
I. To turn off Page dimming, visit about:config and change the preference findbar.modalHighlight value to false.
II. Similarly, if you don’t want Firefox to highlight all occurrences of a search term in a page, change the preference findbar.highlightAll value to false.
READ: Firefox 52: Cortana-related Code removed from Firefox Search
I can’t get the ‘highlight all’ feature working. If I select a word on a web page, then hit Ctrl+F, the find bar opens with that word inserted, and with the “Highlight” button pressed. However, the occurrences of the find term are not highlighted. They only become highlighted after I press the “Highlight” button once (to switch ‘highlight all’ off) and then press the button again (to switch ‘highlight all’ on again).
This happens both on Firefox 51 and Firefox Nightly.
What could be wrong here, or does this work as intended with everyone else’s Firefox?
You may need to reset Firefox or create new profile.