Hi, thanks for such a quick response.
I understand the response from the point of view of "yEd is only a drawing program".
But since the hierarchical algorithm "respects" directed edges, then it seems that at least part of yEd also respects what it means for an edge to be "directed".
Granted, a random graphml file might not contain (yEd-Compatible) information for yEd to pick up the drawing style of an edge but that can definitely be inferred by the `edgedefault` attribute (See for example: http://graphml.graphdrawing.org/primer/graphml-primer.html#BCfile
The editor is by default supporting directed graphs which is clear (there was no "misunderstanding" about this by the way).
If the underlying edge style is undirected, no arrows are placed but if it is directed, the direction can be respected.
The issue of the direction of the edge and the placement of the arrow being two different things is very easily resolved. I cannot think of a use case where it is impossible to align the placement of the arrow and the direction of the edge beforehand, EXCEPT UML associations (e.g. composition/aggregation) where the direction and the placement of the symbol would have to be opposite. But such an edge has specific semantics and it would not originate from a "random" graphml file.
In that case, if the graph had to be saved in graphml I would expect that it contained enough information for its visual style to be set via (for example) the properties mapper.
But in the opposite case, where it is possible to infer the direction of the edge and the edge itself does not have any other data by which to decide the direction of the arrow why not use the directed style from the beginning?