If I create a stereo group, I see a L/R panner. I can double-click the panner in the MixConsole to see a big panner. If I create a 5.0 or 5.1 surround group and double-click the panner, I just get a blank/black window.
The manual says there should be a surround panner for a group (page 115).
I have tried giving the groups an assigned input and output in the routing and also leaving them empty/blank. In my case the surround group is being sent to a surround audio track.
Tested in Cubase 7.5, 8.0.5, 8.0.20, Mac OS X Yosemite 10.10.5, two different computers/audio interfaces. Thank you.