In Mathematica v12.0,The function GraphPlot
seems to give unexpected results when I try to draw a multigraph.
GraphPlot[{{1 -> 2, "a"}, {1 -> 2, "b"}, {2 -> 1, "c"}},DirectedEdges -> True, VertexLabels -> "Name"]
I have noticed this answer that shows this is a bug introduced in version 9, fixed in version 10. But my experience indicated that it still exists on version 12.0. I don't know if it was my mistake or the truth?