On a real G5 HSI, you press the right knob once to get the bottom menu, scroll horizontally to the desired setting, then press again to activate that setting. To set the CDI, you would press once, scroll right to highlight, press again, then rotating the knob will bring up the "VOR" window allowing setting of the radial. On the sim, selecting the "Course" window and pressing the knob instead makes the menu disappear (as in normal use). The knob then adjusts the CDI, and does not revert to setting the heading, as it does in a real G5.
Further, if I use the steam-gauge CDI to set the OBS, it does change in the g5. However, after changing the radial with steam-gauge OBS, the knob on the G5 now operates the OBS instead of the heading also. This makes using the autopilot while crossing a fix requiring a change of radials (e.g., inbound to outbound on an approach or airway) very difficult.
Having the buttonology conflict with the real device seems like a problem.