One recovery worker and store serve every open document. Each document
keeps its slot (record id, revision, timer) and is ticked in place, parked
or active. Closing a document deletes its copy, Don't Save when quitting
does too, and a clean exit covers every open document. File > Recover
lists only copies no open document keeps; Restore opens a copy beside the
open documents or in place of an untouched blank one.