If you are filling out a questionnaire, especially on a device with a smaller screen, often you do not see all answer categories at once because they do not fit in your screen. This could lead to some confusion because there is no scroll bar which immediately pops up to indicate that you should scroll down.

To improve this it would be helpful to have a scroll bar that is always visible if not all categories fit on the screen and it is at least as clear as, for instance, the progress bar on the bottom.