https://bugs.winehq.org/show_bug.cgi?id=43691
--- Comment #12 from Gabriel Ivăncescu gabrielopcode@gmail.com --- Created attachment 68567 --> https://bugs.winehq.org/attachment.cgi?id=68567 Implement cloaking
Here's a patch that implements cloaking. It's quite big because it implements manual cloaking as well (which an app can) by setting the opacity of an X window to zero and making it invisible to mouse input via XShape. It uses the undocumented user32 API SetWindowCompsitionAttribute that I have written tests for (not in this patch). Of course an app will probably use DwmSetWindowAttribute instead, which will be just a wrapper to this eventually.
The shell cloaking itself is not big, but it should do what you needed. I tested on Windows 10 to mimic its behavior and indeed, windows on a different Virtual Desktop cannot be set to foreground (it fails), while manually cloaked windows can, so I only made it fail on "shell cloaked" windows (those are the windows that are hidden by the WM on a desktop switch).
Please test and let me know if it works for you. Don't forget to run tools/make_requests after applying the patch in the wine directory.
Obviously I will split it up and add tests when sending it upstream, this is just a preliminary look at it and looking for comments/testing.