Selections: cannot set default value for Radio group field (nor static dropdown)

You can add a Radio group field to a document type in the document type editor, but you cannot select a default value for it.

When you add the value in the prototype node through the console, the default value does work correctly. It is used in new documents, and it shows the correct radio button correctly in the document type editor too. But changing it there is not possible.

This may be a a problem in other Selection fields as well, please check.