I just did a test, and MT stripped out the comments. So this may not be a workaround you can rely on.
When entering multiple selectors in the code editor, the comments should always stay for all selectors other than the first selector. Only the first selector syncs with the UI fields, the others don’t, and so the custom comment stays. I’m not sure why your body comment wasn’t stripped out. There must be some other factor at play, but just wanted to gives you a head up that it won’t always work.