Excellent! :-) I've just compiled the new source and this is the result:Latest UI fixes
I have also had to trash the previous mame.ini and mess.ini config files (and also ui.ini just to be sure) otherwise the situation, even with the new binaries, was the same as before: starting a new configuration from scratch was safe and produced the result above.
Beautiful and clean. Now I can rely on the embedded UI only, no more need to use external frontends. Many, MANY thanks again to the wonderful MAME team!