We use a custom user field, require it at registration, but do not want users to change it afterwards via account settings. As per your instructions, we set up a custom user field and mark it "Editable only once" under "General Options". Now, if a user registers and sends the register form with errors, the register screen shows again, this time with an error message where the details of the error are specified. BUT, and this is a major bug, all custom user fields specified with "Editable only once" (even IF required and sent empty or with a wrong value/error message the first time) do NOT show up again! So a new user CAN successfully register without the required custom user field. Please specify a bug fix to solve this, we need to patch our installation urgently. Thank you.