Operating system: Wind10
Graphics card: GTX970
inconsistent/unexpected transform orientation when in Normal Orientation mode for multiple selected
While in Normal Transform Orientation mode. Create plane, go into edit mode, select two edges, rotate on the z axis. The transform orientation displayed is not the averaged orientation of each edge.
Normal Orientation for multiple selected edges is incorrect. Single edges are correct but two opposing edges select on a plane do not produce the same normal orientation as the face of the plane.
Here is an example of the axis not updating when I rotate the geometry.
More examples of testing:
I would suggest testing the normal orientation and how it behaves with edges and see for yourself. I'm not sure if this is a bug or a limitation.