Hi there !
This is a bug report. I hope you can confirm this or it is already a known issue by now.
LR is open in a Windows 10 virtual workspace. Then I switch to another workspace (Windows Key + Right arrow key) open a browser or whatever.
When I came back to the previous workspace (Windows key + Left arrow key), LR is minimized and it remains minimized, no way to maximize LR window again.
I had to right click on LR icon on task bar and choose "close window".
Sorry that Lightroom remains minimized when you switch to another workspace on a Windows 10 computer in a virtualized environment.
We've been reported with similar issues on our Lightroom feedback community.
Though the issue is different than what you're reporting, I'd still recommend that you please take a look at the suggestion mentioned in this discussion: Lightroom Classic: Swiping between multiple virtual desktops always snaps back to Lightroom on macOS | Photoshop Family … and let us know if that helps.
No ! It is not on a virtualized environment ! It is on a regular desktop installation. The virtual workspace is a native feature on the latest windows 10 updates (2018 Spring update if I am not wrong).
The solution suggested in the indicated link applies to MAC OS only.