The OS3 version doesn't look as before with AmiModRadio, there is something wrong with that dashed line around the images:

Of course it isn't only with AmiModRadio:

Edit: No, it isn't a bug, as I've been told "Bitmap frames can be used on truecolor screens only. On colormapped screens you get that SHINE/BACKGROUND dashed frame instead to give you a hint that the intended frame cannot be displayed."
But the thing is that in fact those bitmap frames (the borders of the buttons and image) were displayed in colormapped screens.
Now a program like AmiModRadio that includes in the program (not using the MUI prefs) a frame around the Radio image and also around the buttons can't show it like before. The option is to make it invisible with the MUI prefs so you don't have that frame but also you get rid of that ugly dashed lines.

Or to add a frame with the MUI prefs.
EDIT: I'm very sorry, it seems that the problem isn't this MUI version, it was just the preferences I was trying it seems.