Despite respectable variety of
display-buffer-* functions some of them stand out with lack of flexibility, such as
display-buffer-below-selected that exist in absence of reverse variant.
Assuming that decision was intentional, I would like to know what limitations are stopping these procedures from following the suit, or if there exists an easy way to create opposite implementation on the spot using existing inventory.
To make it more clear, here's my own attempt at making
display-buffer-above-selected which only exposes the duplication that lays burden on those that seek to replace missing functionality.