Currently, any click in the node editor triggers a dependency graph update. This forces a redraw if the 3D view is set to Rendered View and the render engine is Cycles. For a complex scene, these forced redraws could be very annoying to live with.
This Diff does a check to see if a node is active and if the current spaceNode is flagged as "is_updating". If so, it still fires the update. But if not, the update is suppressed.
This eliminates the unneeded forced redraws but also keeps full functionality.