randywombat wrote:
I tried to drag one account right to the top of the list, and I guess I must have dragged it a fraction too far because now it's vanished!
That's amazing - I was just about to post saying exactly the same thing! I tried to drag my main current account to the top of the list and lost it. I assumed it was just me being particularly clumsy, but it looks like it could be easy too do, and hence dangerous.
I had to restore my accounts from a back up which was a couple of days old and lost a few entries. You can find the procedure here:
http://www.splasm.com/checkbookpro/support.html#13