When I change the order of the sources in the Source Ordering I noticed that the Library with the old videos is not renamed to follow the new order. So when I check a Library of the new source I have also videos from the source having that name before the change. This might be difficult to handle?
Also, it might be a good idea to hint that after reordering the sources you must do SAVE before Apply. If not, the sources will have a “random” ordering and very confusing ;).