Joining again after a session couldn't go on opened your offline changes in a
copy beside the file. They now go on top as one undoable edit, through the
three-way merge branches use. The rejoin asks to resume as the same client, so
layers made offline are yours to send. What can't go in (the same thing changed
both ways, or layers a new client can't make) leaves the server's version, and
your whole version opens beside it so nothing is lost. A server that no longer
knows you merges the same way instead of discarding unconfirmed work.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>