This came out pre 2.6 release.
If you have a user with limited capabilities on categories who can sort some categories but not others you are still shown the option to sort all categories/selected categories.
Perhaps because a category contains hidden sub categories you can't sort all categories.
The checkboxes still get shown because the user is able to move the category into another category.
The interface really should be improved to either remove the unavailable options (would require dynamic adjustment) or at least notices that either they sorting will only occur where they permission to sort OR that the sort action they attempted did not succeed in sorting all selected/all categories.
After discussion we couldn't turn up viable use cases in which this would be encountered, and deemed this to be an edge case.
As such this isn't a 2.6 release blocker and can be dealt with post release.