Windows 8 64bit,
Short description of error
With 2.74 i was able to use clipping border to cut smoke into a slice for better analyzing.
With Blender 2.78 it does not work anymore.
Exact steps for others to reproduce the error
open the file. if you see no smoke press ALT+A, wait for some seconds and press ALT+A again.
press ALT+B to clip border and select a slice of the cube + smoke
In Blender 2.74 it cuts cube + smoke into a slice.
In blender 2.78 it cuts the cube but does not touch the slice.