Seamless windows managed by host window manager

[Hiroe]

Disadvantages of the current seamless module are that you can't have different windows at different strata. One window can't be covered while the other isn't. A native window is either above all the host windows or none of them. Not being able to take advantages of window manager feature like snapping windows, virtual desktops or always on top is annoying as well. To say nothing about how broken seamless mode is on a tiling window manager.

Seamless RDP fixes this by spawning each windows as it's own xserver window, instead of just one window with transparency. I'd like to see something like that on virtualbox, as seamless RDP is not very efficient and can be difficult for users to set up.

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.