In a group structure where a group contains more than 20 objects or possibly more than 20 groups that also contain objects, only the first 20 objects are shown when group by is set to "Parent (Groups)" and the view mode is set to Root Level Groups. In order to view the remaining child objects one must use a flat view which may result in a huge list with no way of searching.
It would be a nice touch if it was possible to either by default show all child objects when there are more than 20 or to have an option to expand the number of objects shown. Alternatively, a way to search.