Since Dapper Drake, my first cup of Ubuntu, OpenOffice and now LibreOffice has driven me mad: 1. Periodic hold-your-breath "document recoveries," 2. Copy/paste fail from cursor/GUI menu and keyboard.

Now I have solved the problem. The culprit is the workspace switcher, which I have never not used. Toggle if off via Settings < Appearance < Behavior and the above problems will disappear.

Perhaps the switcher corrupts the filepath?