Hi Reinout,
Unforunately, mendix imposes limitations on where you can place scroll containers (I am sure it is for a good reason).
Did you try what happens if you add the scroll yourself with css.
Put the following code on your listview under style:
overflow-y: scroll;
max-height: 100vh;
This will assure that the scroll bar is always visible (it will be disbled if the content fits vertically) and that the container will not be bigger than the screen.
Hope this helps,
Andrej
If the standard scroll container is not a good fit, you can give a try to my widget
Scroll Dynamic Height Container
It's basically doing for you the CSS mentionned in the previous answer, it calculates the height dynamically to reach the bottom of the screen with a formula like : 100vh - Yposition