Logos had been running unattended for a couple of hours. When I selected a new layout, it began to load, then L5 disappeared from the screen and an Apple Crash Report dialog took its place.
4188.Apple Crash Report 09-20-13 @ 2057.rtf
0714.LogosLogs.jackcav.20130920-205747.zip
Upon restart, Logos requested an automatic crash report—which was sent.