In the backend you can define sorting-criteria for each category (like: sort by title, descending). But it seems that the parent category overwrites the setting in the child-category.
In my eyes it absolutely makes no sense that the parent-category overwrites the setting in the child-categories. If this is intentionally the setting should not be possible in the child-categories.
BTW I think that the tree-view does not work correctly in the sense above, because the tree-view is sorted as adjusted in the child-category (at least I think so).