Sandbox

{{#sqform:

      {{#input: type = hidden | name = content | value = {{#sask: type = articles | {{#sqvar:mode}}"{{#sqvar:mode}}" is not in the list (Ionian (Major), Mixolydian, Aeolian (minor), Dorian) of allowed values for the "Has mode" property. }}

Has Mode:

{{#sask: ?Has mode}} }}