I have the ML 2.3 stable release on my 50D (firmware 1.0.9 as recommended). Before I installed ML, I had the SET button configured to let me quickly choose different picture qualities (esp. RAW vs. JPEG). Now, when I press SET the blue light blinks but nothing else happens. I made sure I have "Use SET button" turned off in Prefs->Arrow/SET shortcuts but that doesn't seem to help. (I also tried turning it on in case I misunderstood the setting.)
The SET button does work "the Canon way" in Live View. It also works the way I want when I boot without ML.
Based on previous ML experience, I'm assuming that I have some conflicting setting. Any suggestions on what it might be?