I hit a combination of keys by accident, and it changed the display to something way different that I don't want.  I managed to get things back to normal, except that the volume level meter in each track is now below the controls and horizontal, instead of to the right and vertical.  How do I get it back to vertical??
 
Edit:  A couple other things as well: The Event List, Piano Roll, etc., are now all at the top instead of the bottom.  The Browser is on the left instead of the right, and I've lost some controls on each track.  I really need to put things back the way they were. :-\

It sounds like you have switched screenset:
https://www.cakewalk.com/Documentation?product=Music%20Creator%206%20Touch&language=3&help=WindowManagement.7.html
 
 

Aha!  Yes, that was it, thank you!

I searched the docs for "display", "screen display", "default", things like that.  Never would have thought of the word "screenset". ...