When adding a new payee name during manual transaction creation, if you have "Auto-review transactions on manual creation" enabled (under Settings), then the expected behavior is for the new payee name to immediately show up in the payee suggestion dropdown.

This works for payee names added during transaction creation via the Transactions table (full width screens). It doesn't require page refresh.

However, when adding a new payee via the 'Add new transaction' panel (on narrow screen widths), the new payee name doesn't automatically get added to the suggestions dropdown. You have to refresh the page first.