I'd like to keep the values in their current order but have the second one "first_of_the_coming_month" be the default. It's easy enough to do this in the regular drop editor but the advanced editor doesn't let you assign a default as seen below. I'd like to request this feature be added in a future update. Thanks!
This allows you to select a default value when using advanced options, but it won't work in this case because the menu value is using formulas, and due to their nature we don't allow defaults to be such values.
I'll take a note of this and see if there's a way we can improve it to allow such cases.