"Luma" color space in the histogram setting doesn't work, it's stuck in RGB mode no matter what I choose. But I noticed that if I set Use RAW histogram to OFF, then it works fine.
Tested with: - magiclantern-Nightly.2015Jun25.6D116 - magiclantern-Nightly.2015Jun25.60D111
I'm not sure when it stopped working. If you need more details just let me know.