I didn't delete the Songbook but I did start over with my songs.
When I set up my songs I saved each of them with a special Genre name. I arbitrarily used the number 1.
When I turn on the keyboard the first thing I do is touch Songbook, then Filter, then touch Genre and then enter 1.
Then apply the Filter and MY list of songs is displayed in alphabetical order.
All this takes maybe 5 seconds. If I want to see the entire list, including factory entries I can simply deselect Filter by touching the display and reselect the same way.