Is the data supposed to be saved on the server, similar to a draft email message on a webmail site, or in browser/offline storage? I don't know why there would be a problem with saving on the server, but there are some privacy and anti-cookie features that could block offline storage.

Yes, the data should be saved in the browser but isn't for some reason, it might be an anti-cookie feature, but I don't have any selected or anything installed that should be causing this.

I am using the standard protections in the browser settings.

Okay, so there are three possibilities (at least):

• Failure to store data, but no error displayed to you by the site
• Data is lost between saving and editing
• Failure to retrieve/restore data when you want to edit

Firefox's Developer Tools have two panels that might be useful. One is the Console, which should show any error message associated with actions taken by scripts in the page. The other is the Storage Inspector, which shows what is saved in various categories of browser storage. Here are links to some pages describing these two tools. (For storage, this display sometimes doesn't update correctly and you may need to close and re-open the panel in that case.)

• Web Console - Ctrl+Shift+K - https://developer.mozilla.org/docs/Tools/Web_Console
• Storage Inspector - Shift+F9 - https://developer.mozilla.org/docs/Tools/Storage_Inspector

I will also mention two extensions that provide backup form entry storage. I haven't used them myself.

• https://addons.mozilla.org/firefox/addon/textarea-cache/
• https://addons.mozilla.org/firefox/addon/form-history-control/