That did the trick. Thanks Tim!

After I complete a flight, the flight course is still displayed on the map. If I click the quick access "Clear the current flight plan from memory, and start a new flight plan", I get new blank flight plan but the previously flown course is still there. I can even create more plans and fly them and they all stay displayed. How do I get rid of them? Clicking New Plan from the file menu also clears the flight plan, but the previous track is still on the map.

If I disconnect they go away, but when I reconnect there they are again. Only exiting and restarting the program gets a clean screen.

I'm using a networked laptop and connecting with FSUIPC and WideServer.   Plan-G version 3.1.2.101