I try to avoid the Runtime dialog whenever possible. This one is due to the choice for using Submit All. Just a warning (off topic, I know): this means that no results are transferred to the LMS before all questions are answered. Unless you are very sure about the connection for all mobile devices, I would not risk to choose that setting.

Responsive project with FLuid Boxes or with Breakpoint views? There is no way to have that runtime dialog box in a fluid box, hence the problem. You may log a bug report, to be heard!