Cinnamon: tranferring ALT to virt-manager

[Alex]

Hi,
I have a kvm instance running win10 and need to use the ALT-click key
within the instance. However, it seems Cinnamon is intercepting that
keypress when accessing the instance using virt-manager.

It works fine with virt-manager and GNOME, just not with virt-manager
and Cinnamon.

virt-manager isn't my favorite, but I've also tried tigervnc some time
ago and it also has the same problem.

Is there a virt-manager config options I need to select in order to
pass the ALT + left mouse key through to the instance?

It's currently just set up as a PS2 mouse.

Here is my qemu xml config
https://pastebin.com/Pnizy4Q7