Restarting the TeamViewer service should solve the issue:
Thanks very much for your well documented restart procedure. I'll save this trick for the next time I have this problem, but for now the issue has resolved itself without any intervention. Prior to this sticking point I had been getting TV solicitations on top of my main screen to purchase TV (I'm using the free version for control of my ham radio station), and that ad could be dismissed until it got stuck as shown in my original post. Thanks again.
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