Thomas,
re: songpicker in multipicker - rebuild
You're correct about that, and it will be fixed in next patch.
There's an easy workaround, just open the songpicker as a standalone (click the song picker button while holding the shift key), and the songpicker opens as a modal dialog where you can rebuild as usual with the button.
As mentioned, the next patch will make the rebuild work in the multipicker as well.

btw) that 'trick' about holding shift works for many of the pickers, if you prefer to open them as standalone. And there is a global setting on the Edit menu that determines what the default will be (multipicker vs modal dialog)

Have Fun!
Peter Gannon
PG Music Inc.