https://forums.flightsimulator.com/t/cannot-pop-out-g1000-panels/586423
https://forums.flightsimulator.com/t/su-12-popup-instrument-windows/584205
https://forums.flightsimulator.com/t/how-get-pop-out-window-back/587914
https://forums.flightsimulator.com/t/instrument-pop-out-not-working-anymore/597966
I think these discussions could provide some useful information or potential solutions for you. Hope you find them helpful!