The New Transaction screen always defaults to using an account of mine that is marked as hidden and does not show up in my list of accounts on the iPhone.
This isn't a problem with most transactions because the account changes as soon as I select a known payee.
But if I'm entering a new payee then it's one more thing I need to change before I can put my phone away. And if I forget to change it, once I sync with desktop YNAB I end up entering it again (and throwing off my budget) because it's in a hidden account and I didn't know it was there.
I wonder if it's possible to make the default account for new transactions be the account most frequently used in the past 6 weeks? That would be handy.