My PC connected to 2 monitors with different display resolutions: 1366x768 (main) and 1280x800. It is always running a WPF app with maximized. I want the second monitor will show an image or video in normal condition, but it can mirror some windows of WPF if I determined.

Therefore I tried to use display mode of windows to switch between extend and duplicate mode. But the resolution of main screen is changed after switching to duplicate mode. Also, the main screen display black screen during the transition.

Are there any solution to solve this problem?

Thank you very much.