This works with absolutely all RF components out there (modal panels, datatables, etc.):
1. enclose the list in a div;
2. set fixed width and overflow:auto in the div's style;
3. for crossbrowser compatibility sometimes it's a good idea to set z-index for both the div and the enclosed RF element with the z-index higher for the div;
Hope this helps
Thats how I have done it for now.
The trouble is when you have a orderingList that is wider than the space available and it shows the scrollbars, the vertical scrollbar is then placed at the right end of the panel, which is not shown, because the list is wider than available width, so you have to use the horizontal scrollbar to scroll right to get to the vertical scrollbar at the end.
Do not limit the list height but the div's then.