Hi Dave,
I've read a couple of posts regarding this topic so I wanted to pass this along. I will continue to monitor the issue and will provide additional information when I get it.
As mentioned in the title, I have experienced several instances in the past when the co-pilot "takes over" even though those options have been de-selected. In this specific instance (which has occurred more than once), I was monitoring the Speech panel settings while nearing the take-off runway as I taxied towards it. I had been "communicating" with ATC and controlling frequencies to this point. Neither the "Responds To Radio" nor the "Changes Frequencies" boxes had check marks when I began taxiing. As I drew near the active, Ground instructed me to contact the Tower. At that point, I noticed the "Responds To Radio" and "Changes Frequencies" boxes became "checked" and the co-pilot changed the frequency (which was set to Ground) to Tower and contacted the tower.
I have attached screen shots of both the Speech Panel and the Buttons Panel in hopes they will assist you in telling me what I'm doing wrong. I will continue to run P2A with the Speech Panel open as I fly, to capture any additional instances of this "unrequested" change and will provide you with any relevant screen shots to, again, assist in determining where I have erred.
Thanks.
Ken in Kansas