Occasionally you may see a Draft message appear in the upper-right corner of your diagram. Draft messages appear when the browser detects that it may have work that was left unsaved, or if there were any network or connectivity issues while working on a diagram. These ensure that no work is lost inadvertently.
You can Preview Draft to see if it is a version you want to keep, Load Draft (this will override current draft in the editor), or Discard the Draft.
If the Draft does not load the browser has cleared the draft from it’s history. Drafts only store the most recent browser history.