In some of the earlier versions of Money, the drop down for entering the "Pay To" field into the register will stop working on February 29. It only occurs on that day, not the previous or following day.
If you add a new payee in the "Set up your payees" window, the the added payee shows up in the register "pay to" dropdown only if there are no transactions for the new payee. Once a transaction is created, the payee no longer shows up in the drop down.
This bug only manifests itself on February 29, so it shouldn't be seen again until February 29 2012. Microsoft have indicated it won't be fixed for earlier versions of Money (this bug appears in Money 2004 and earlier)
Keywords: Pay To, Payee, Bug, Payto, Feb-29