I'm having a bizarre issue with virt-manager that seems to affect only Linux guests. In particular, when I select View -> Resize to VM there is a variable sized black border around the VM, as shown:
The reason this is a problem is that, when I set the guest screen resolution to 1920x1080, which is my laptop's native resolution, then go View -> Fullscreen, I get the black borders there too, and scrollbars which interfere with actually using the guest at its bottom and right edges.
This doesn't happen with a Windows guest; it appears normally in both windowed and fullscreen, with no black borders or scrollbars. For example:
In addition, a RHEL 7 guest also appears normally, with no borders or scrollbars in full screen mode. As far as I can tell this is specific to Fedora guests.
After some experimentation, I discovered this only happens when the guest is running Wayland. When I switch to GNOME on Xorg the borders and scrollbars disappear and the guest is usable again.
I am running Fedora 28, with virt-manager-1.5.1-1.fc28.noarch. The guest in question is also Fedora 28 with xorg-x11-drv-qxl-0.1.5-6.fc28.x86_64.
What's going on here? I need to get rid of these black borders and scrollbars in fullscreen mode. Turning off Wayland is a workaround, but I'd like an actual solution, so I can continue to use Wayland.