Dejaclick not available on Firefox 59.0.3?
Firefox version 57 and above prevents all traditional plug-ins from working, including DejaClick. To record DejaClick scripts in Firefox you need to use an older version of the browser. The Remote Locations use Firefox 52 currently, so this is the best version to use if possible. Link below to both 32 bit and 64 bit versions from Mozilla.
Install this version in it's own new folder, and make sure you go to 'Options - General" and scroll to the bottom for Firefox Updates and check "Never check for updates". This prevents the browser from upgrading in the background by accident.