Firefox English GB Dictionary not working, why not?

Question

I had three dictionaries installed and working fine in conjunction with spellchecker in FF 19 - but having updated to FF 22.0 only English (United States) is included. I have added English-gb numerous times and done numerous reboots and or FF restarts but the English-gb is simply not an option when spelling check queries spelling. The English-gb dictionary shows up in my add-ons but it simply does not work. (the add-on is not disabled either).
Also adding words to a dictionary doesn't appear to work either and may be related.
To summerise: The English-gb dictionary is added as an active add-on but it does not work!
Operating system Windows 7 Ultimate.

Answer 1

Try to disable all other extensions.
It is possible that there is a problem with the file(s) that store the extensions registry.
Delete the extensions.* files (e.g. extensions.sqlite, extensions.ini) and compatibility.ini in the Firefox profile folder to reset the extensions registry.
*https://support.mozilla.org/kb/Profiles
New files will be created when required.
See "Corrupt extension files":
*http://kb.mozillazine.org/Unable_to_install_themes_or_extensions
*https://support.mozilla.org/kb/Unable+to+install+add-ons
If you see disabled or not compatible extensions in "Firefox/Tools > Add-ons > Extensions" then click the Tools button at the left end side of the Search Bar ("Find Updates" button in older Firefox versions) to check if there is a compatibility update available.
If this hasn't helped then also delete the addons.sqlite file.
You can also try to delete the localstore.rdf file and the sessionstore.js file in the Firefox profile folder
Deleting sessionstore.js will cause App Tabs and Tab Groups and open and closed (undo) tabs to get lost and you will have to recreate them (make a note or bookmark them if possible).
*http://kb.mozillazine.org/Session_Restore
*https://support.mozilla.org/kb/restore-previous-session