Actually, that was one of the first things I've checked.
By now, I have already kicked out the old userPrefs.mel, made a fresh start and everything seems to be fine now.
Seems that something had gone wrong with the old prefs file anyway, since I always got this annoying message in the script editor at startup: line xxx - value out of range.
I think I'll go back to blender...
No really - because of lack of time (and talent) I had already considered selling Maya, but selling Maya is not allowed, so I'm stuck with it...
Lots of thanks anyway.
Subdivide and conquer!
Free your mind, and your ass will follow!