Rate behavior: a draft always uses the customer's current hourly rate, and it is refreshed each time you save the draft. If you change a customer's rate before approving, save the draft again to pick it up. At approval the rate is frozen, and later rate changes don't affect that invoice. Check the rate in the review window before approving.
Invoice status: every invoice is a draft, approved, or void. Only drafts can be edited, only approved invoices can be voided, and only voided invoices can be reissued.
Weekly reminder: each Monday at 8:00 (server time), project owners get an email listing their active projects that have no non-voided invoice created that week. If a project's Owner is an email address, the reminder goes there. If it's just a name, the reminder goes to the default reminder address (hello@suiteresources.com unless configured otherwise). Voided invoices don't count as billed.
Dialogs: pop-up windows only close from their Cancel or × buttons or the Escape key. Clicking outside them does not dismiss them, so you won't lose unsaved work by accident.