Virt-manager and guest window stop reacting after some time-out

[Leon Pollak]

Hello.
After upgrading to FC38 I have the following problem:
After some time of inactivity (working in other windows in my FC38 KDE
machine), returning to the virt-manager (4.1.0) and guest window does
not happen. I see the window capture displaying "Virtual Machine
Manager" or the name of my VM, but nothing happens.
I still can switch back to the host machine.
If I run "systemctl restart libvirtd", close all windows and run
virt-manager again, after providing the root password everything
returns to its normal state - the guest continues to run (from the
same place), manager is working normally.
Till the next "time-out" which is rather "long" - about 10-15 minutes.

Does someone know what to do in such a case?

Thanks
Leon