System Information
Operating system and graphics card:
Mac OS 10.11.5 / 10.11.6
NVIDIA GeForce GT 650M 1024 MB
Blender Version
2.7.8
Short description of error
Material graphs are not showing in supplemental node editors. So - in a basic scene with a cube that has a cycles material, the graph will show if the principal 3D view is switched over to a Node Editor. If however a 2nd view is opened adjacent to the existing 3D view, the node editor will not show any items in the graph. In some instances moving from the Default to the Compositing layout allows to show material nodes adjacent to the 3D model view, but this does not work always.
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps



