External diff tool doesn't run on the correct parent file (merge diff)
Created originally on Bitbucket by DaveInCaz (David Hollman)
In a merge changset commit view THG shows a  and  button above its diff view. These select either parent of the merge.
However when you use the "Diff to Parent" comment (^D) it ignores which button you have pressed. It always seems to diff to parent #1. I expected it to be consistent with THG's own diff view.