Why does FishEye say this changeset is on more than one branch? Why does that changeset have multiple parents?
Perforce allows a single changeset to include files on multiple branches, so FishEye marks those changesets as being on all of the branches involved.
When a changeset is on multiple branches FishEye may consider it to have multiple parents from the different branches.
FishEye does not track merges in Perforce, so merges are not shown in the graph.
Changeset branches and parents are only annotations at the changeset level --- the individual file revisions will each only have a single branch and at most one parent.