I spoke with a support agent, and he walked me through temporarily changing the payroll account so the tax deposit can be entered correctly. Here's the process:
1. Click the gear icon, select Payroll Settings
2. At the bottom of the list click the pencil next to Accounting
3. Click the pencil next to "Paycheck and payroll tax payments"
4. Choose your payroll tax account.
5. Click Continue, Done, and Done.
6. Enter the payroll tax payment (the bank account should now be the account you selected above)
7. After recording your payment, repeat steps 1-5 above to set the bank account back to the payroll bank account so your paychecks are entered correctly.
Hopefully the programmers will realize this "upgrade" was a mistake and correct it, because it would be so much easier to just select the tax account when entering the liability payment. But for now, this workaround seems to do what needs to be done.
