Sandbox

{{#sqform: {{#input: type = hidden | name = content | value = {{#sask: type = properties | [[Has mode::{{#sqvar:mode}}]] }} [[Has rhythm::{{#sqvar:rhythm}}]] }} }}

Has Mode:

{{#sask: ?Has mode|return = mselect}}

Has Rhythm:

{{#sask: ?Has rhythm|return = select}}

{{#input: type = submit | value = Ok }} }}