This was a motivation for the design of UWP apps (which use a different approach to window management, involving a dedicated system process that is responsible

This was a motivation for the design of UWP apps (which use a different approach to window management, involving a dedicated system process that is responsible for drawing and managing all the window frames), as well as how they were originally presented differently from Win32 apps in a separate "area" back in the Windows 8 days. It's extremely difficult to make any significant change to the paradigm of how Win32 apps are managed and presented and have it work consistently for arbitrary apps - for example they recently tried to add a feature to Windows that allowed arbitrary native apps to be switched and managed via a tab strip like web apps. Worked fine for UWP apps, but when they tried to extend it to arbitrary Win32 they got mired in edge cases and eventually dropped the feature.