Comment # 4 on bug 1143558 from Martin Vidner

Thanks for the report.

Yes. It's because libyui has no concept of a scrollable VBox.

Therefore we simulate one with a RichText widget[1]. When you select a role, we
have to replace the text to put the selected "radio button" in the right place.
Replacing resets the scroll bar.

[1]:
https://github.com/yast/yast-installation/blob/b7e93db8a3223d3d47e989e491348f2761c07430/src/lib/installation/select_system_role.rb#L270