Microsoft is still polishing Windows 1
This feature is part of Insider Preview Build 18329, which Microsoft announced on February 1, 2019. If you have a Windows Mixed Reality headset, you can now launch a classic Windows desktop application in the Mixed Reality environment. They will float in 3D view as window panes, just as Universal Windows Platform (UWP) app from the store is already doing today.
How Microsoft says it works:
To use this feature, record Pins Panel [in Mixed Reality] then go to all apps, where you will find a folder named "Classic Apps (Beta)". In this folder, you can select and start any Desktop program (Win32).
While this is pretty cool, it really is not super practical. Today's virtual reality heads have fairly low resolution panels, and you can see the pixels when your eyes are close to each other – it's the "screen door effect." But a future super-high resolution headset can possibly provide a good workspace. Windows Mixed Reality is now ready for that future.
RELATED: What is mixed reality on Windows 10, and should you buy a headset?
The latest building also contains "Top apps" in the new search interface. When you open the search view, Windows will suggest the apps you have used the most, at the top of the view.
The Windows 10 keyboard now includes support for the ADLaM script used by the Fulani people in West Africa and the Osage script used by Osage Nation in Oklahoma  RELATED: All New in Windows 10 April 2019 Update