For real world flying I use Skydemon. When trying to open it in VR as “classic app” in WMR “cliff house” sometimes it opens in VR and sometimes only on the 2D (normal monitor) desktop. When it opens in 2D only, in VR I have still the window open but the window content is just black or presents Skydemon application icon. When I click on it in VR, it results in “Loading circle” visible in VR and opening another instance of Skydemon on the 2D monitor only.
When Skydemon starts every time it displays a window for conditions confirmation which is visible on 2D screen only and requires pressing Enter, what I do.
Sometimes it works in VR properly, I can interact with the program with the mouse or VR controller. But sometimes it acts crazy, like going to sleep or not being visible in VR.