If you are working on a notebook and for whatever reason the server or the crashes, there doesn't appear to be any way to reconnect once the server comes back to life. Unless I'm missing something, the result is that anything written since your last save must be copy/pasted into the last saved copy (or given up as lost..).

This is related to #1378 (autosave), #2553 (robustness against client failures) and similar to #2667 (can't save if accidentally deleted), though it seemed to me a somewhat different issue, so I've given it a separate ticket..