Since Zenedit plugin version 2.0.0, two new features were added - Drafts for checklists and wiki.
The original draft feature of the Zenedit plugin was designed for the Redmine issues only. More information about it could be checked in the following documentation article.
Now, if you have opened an issue and added/edited some checklists only, and then accidentally close the issue, browser, etc., then when you reopen it, the draft feature will warn you that you have unsaved checklist changes.
Note: Please note that for this feature, you have to install the Checklists plugin first.
The same is valid for the wiki section as well. If you have closed by mistake a wiki without saving it, then the drafts feature will help you out afterward to recover it.