Disable ability to add new entries in Enum or Enumlist of Ref type in Dropdown mode

[Encrafted]

Exactly what it sounds like. I uncheck "Allow other values" but I have a vague idea it doesn't work because it's a reference type.

People can click the "new" which takes them to this:

Obviously I don't want this, I want someone to select from the pre-determined options. I don't see how Valid If would help in this scenario either. 

I've just realised I can sort of hack it by unchecking "show" back in the Repeat spacing table so if someone tries to add a new entry it takes them to a blank screen. Not really an ideal solution.

[Encrafted · Accepted solution]

Never mind, I've solved my own stupidity again. I just needed to disable the ability of AppSheet to change the referenced table. I forgot that was a thing.