Hog2PC: Encoders don't respond

I am running a show with a pair of VL1000s on Hog2PC. When I try to change any parameter using the encoders, the encoder wheel spins with both the mouse and the keyboard shortcuts, but the parameter remains a '?'.

I loaded my backup copy of the show and now it works. What parameter did I inadvertently change?

thanks,
Dan Howden
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