I created a form with 2-3 radio buttons. Then I used this form as a subform in another form.As we know in the new form the radiobuttons are shown as dropdowns. 

My question is, I am trying to adjust the radio buttons width (dropdowns in the subform) manually but they are not shown in the Configuration pop up. Why this happens?

Is it a bug or is is something else? Is there any explanation for that?