The Play List 1.5

Your iTunes Music Library is loaded into the Track Browser

Your iTunes Music Library is loaded into the Track Browser at the bottom of The Play List window and displayed in green.
Double click tracks in the Track Browser to build up a PlayList.

The PlayList is directly above the Track Browser in the center of the window, and is auto-saved when you exit the app. So the next time you open the app, your PlayList is how you left it.