Data.contact_enabled is gone: an empty contact label disables messaging
(no buttons, no visitor icon, sends rejected). The settings row is one
line — flag selector, label, email, subject as small boxes with tooltip
instructions — and saves re-render the page in place so button/dialog
strings update without a reload; the open dialog also re-reads its
strings on page swaps. The built-in Contact us default survives only as
the inert preview placeholder.