Update broke Ctrl-F and Edit-Find (Find-Bar won't open).
This was one of my favorite add-ons (still 5-stars!)...
I had a previous version of "Regex Find" installed and everything worked fine (probably Version 1.1.1-signed, but I can't confirm that).
After Firefox automatically updated of "Regex Find" to "Version 1.1.3-signed", Ctrl-F and Edit-Find stopped working... the "Find-Bar" won't open.
I uninstalled Regex Find Version 1.1.3-signed.
Regex Find Version 1.1.2-signed is "Not available" for the version of Firefox I'm using, so I reinstalled Regex Find Version 1.1.1-signed.
Everything works fine again now that I'm using Regex Find Version 1.1.1-signed.
It seems that (perhaps) the changes to support "FF 50.0+", or the "New/ Changed Regex checkbox style" broke the Find-Bar. Other users say it was the changes to support "FF 50.0+" that broke the Find-Bar, but I can't confirm that because I cant install/run Regex Find Version 1.1.2-signed.
The versions 1.1.8, 1.1.9 should now work in the versions up to 56. For 57+ you should use Nightly edition and addon installation from the releases section of this repo (currently 1.2.0), alse see the readme for details.