Managed to get minimal line wrapping to work.  That requires a lot of non manetainable, janky, spaghetti.  Cleffs, key signatures, 8va's have to be extended to each line.  There are glitches.  The mouse pointing is really bad.  The replicated cleffs on each line are off by a few pixels, but its far enough along to start letting more glitches slide in order to get somewhere functional.

There's definite contention on the issue of letting bugs slide in order to get to minimal functionality.  On the 1 paw, we're supposed to be doing test driven development.  On the other paw, we're supposed to be making minimum viable products.  Lions have traditionally favored letting bugs slide to get to the finish line.  It was always about the requirements constantly changing, the low odds of it being finished, the low odds of anyone ever using it.  When working with other animals or making a high profile program with frequent uploads, you always have to keep up with the bugs, can't be finish line focused because in that case your quality of work is being judged.

8va line wrapping was the next big one.  Professionally engraved music has the 8va's extend off the end of each line & restart on the next line without any special ending on the previous line.  Take every win you can get.

Undo & redo would be the last step before finally moving into user defined notation.