Please consider warning the user when they perform a “save” includes the deletion of course sections or lessons. I’ve inadvertently lost material while training on the use of WPEP when trainee mistakenly deleted a course section and then performed a quick save.
Hitting delete and then save in most applications creates the end result that content is deleted.
In WordPress revisions eat up alot of memory and resources and for that reasons very many people actually disable them to speed up their sites.
We’re not talking about creating a new habit here but hitting delete and then saving is a set of actions that should be performed with ultimate care.
On the other hand a little piece of advice for you.
Building the courses with the blink of an eye coursebuilder is very easy and fast and i would suggest that you work on your content not directly inside WordPress but use any n ote taking app, doc file or evernote nd then simply copy and paste things over.
That’s how i do it myself too and it works.
All the best