Refresh graphical glitches on an emulated spice display
First of all, sorry if I'm filing in the wrong place, but I have a hunch this is spice related.
When using virt-manager with a default configuration wrt display (spice server on localhost, OpenGL deactivated), I am getting some refresh graphical glitches: when moving fast some objects, it seems like the refresh region isn't properly calculated, leading to some artifacts. Those goes away when you change the focus of the window which, I assume, forces a full refresh.
You can see this in action here, where I move a bunch of code around on a windows VM and changing the focus leads to a cleanup of the window: https://streamable.com/4kcytr
If you prefer screenshots: 
This can be reproduced on a standard virt-manager config on NixOS. I am running under wayland using the WM sway. Nothing else is out of the ordinary, nor any guest tools installed. In this instance I used a PCI passthrough but this also happens without it. It happens on Linux, macOS and Windows VMs too, so probably unrelated.
Thanks for maintaining this software and ping me if you need any help for repro/debugging!