I found that the clim-listener calls format-graph-from-roots with :tree as the graph type, but :merge-duplicates=t. The spec sorta ambiguously suggests that these aren't compatible. Is there any reason why you did this?
Of course, it's possible that this was because formerly there was no layout method for :dag or :digraph, and :merge-duplicates=t would force the choice of one of those methods....
But I had thought about sending a warning if one made this choice, and turning off :merge-duplicates in that case. So I would like to make sure this wouldn't be a problem.
Would you mind having to change to :tree and :merge-duplicates=nil?
Best, R