Seems to be a Mac-only bug. When invoking a Selection-type memory location, the selection shows up and the audio is highlighted (on the track in focus), as expected. But if you renumber the memory location and recall it, the in and out spots are marked on the ruler, but the audio or MIDI only the current track is not selected.
Steps to reproduce:
1. Open a session containing at least one audio or MIDI track
2. Make a selection on it.
3. Hit Enter.
4. Choose "Selection" under Time Properties
5. Hit Enter.
6. Hit return or otherwise place selector elsewhere.
7. Open MemLocs window.
8. Double-click the newly made selection MemLoc and change its Number to, say, 99 and close.
9. Hit Return
10. Type .99.