I made a popup window when I first got the C90. Seems the HDG and CRS knobs do not function on a second monitor in FULL screen mode only. If you go to windowed and undock them in a second monitor, the HDG and CRS knobs work. OR if you run full screen then move the AP/EHSI cntrl into the main screen and back to the second monitor they work untill pressing another button then they stop again. It seems to be a bug. I emailed Carenado, will see how that goes!They had no clue what I was talking about?????????