Some websites use advanced techniques and frameworks involving javascript that make it virtually impossible to capture user input in a generic way. On request I can add workarounds for popular websites/frameworks, please submit an issue and let me know for which website(s) capturing entries does not work (see built-in Help, Manual, Known Issues).

Recent update 2.5.6.1 contains a fix that improves storing entries for many popular javascript frameworks like the cke editor. This release massively increases the number of sites where it is able to store/restore your work.

Older (pre WebExtensions) versions of Form History Control stored extra information in the cleanup.sqlite file. This file is located in the root of your profile folder, you can simply delete this file.

For an explanation on where to find the profile folder see: https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data.

I do provide an export/import utility, see: https://github.com/stephanmahieu/formhistory-export

There is a clean-up feature: if you open the details of an entry you can either choose to copy all (including the HTML-junk) or just copy only the bare text.

Having trouble? Consulted the manual? Please contact me or file a bug report if you are having issues getting this add-on to work.

Hi
sqlite is no longer available for add-ons, HTML5 client side storage is commonly used instead. This is implemented in Firefox using IndexedDB.
See for instance here: https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API/Basic_Concepts_Behind_IndexedDB