Preventing a custom field from being displayed


I’ve added a transaction custom field to one of my queues, which is
functioning more or less how I would like it to, but I’m wondering if
there is any way to prevent it being displayed when creating a new
ticket, since it’s only relevant on updates.

I tried checking the URL, and not outputting any html in
local/html/Elements/EditCustomFieldMyField, but the label and
description are still being displayed.

Is this something that can be done?

Thanks for any help,

Jon Wood