Quiz Master Template

I wanted the quiz question to have a distinct background:  visiting the slide master, editing the quiz master, it is easy to make the quiz title, which is used for the question, to have a border, and background color which makes it stand out from the choices.

When I select Format Shape > Text Box > Internal Margin ... to add some space between the question and the border, it does take the values, but the extra space does not show up in the rendered quiz questions, as if nothing had changed the internal margin at all.

Is there a better way to get the question surrounded by a border without the border resting against the question text?