Seamless Mode opens no fully transparent Window

[Woccam]

System: Host: OpenSUSE Leap 15.0, KDE, Dell Precision 5520, Dual Screen (1920x1080 internal lcd, 4k external Monitor) Guest: Win 10

When I switch to seamless mode on the 4k Display the transparent overlay window keeps a non-transparent area that could overlap on other host windows so that they are no longer acessable.

[Woccam]

Screenshot

[MyCatsNameIsBernie]

I have same problem with 6.0.0 using a MacOS host and Windows 10 version 1809 guest. On the Mac OS X Hosts forum, I was advised to change the Windows desktop background to a solid color. It didn't fix the problem, although it did change the behavior slightly. Starting in windowed mode, when I enter seamless mode with a solid Windows desktop background color, the Windows 10 desktop fills the entire screen. However, the desktop is still opaque. With a picture as the desktop background, the desktop only expanded to the upper left quarter of the screen when entering seamless mode, and was also opaque.

[MyCatsNameIsBernie]

See very similar bug #18022.

[Socratis]

This does indeed seem like a duplicate of #18022 (or vice versa), but more information on #18022.

EDIT: Actually both of #17922 and #18022 seem to be a duplicate of #15092. Just on seniority alone...

[janitor]

#15092