virt-manager 3.2.0 error "Argument 1 does not allow None as a value"

Hello,

yesterday I managed to get virt-manger 3.2.0 to start on my ubuntu 18.04 LTS. Before I had to install some modules but it starts at the end without error. I also was not even able to start it, the installation worked as well.

But today, when I was digging deeper in, I get the following error, when I hit the VIrtIO Disk 1 item in the details page of a machine:

---

Error reloading device page: Argument 1 does not allow None as a value

Traceback (most recent call last):
File "./virtManager/details/details.py", line 1724, in _refresh_page
self._refresh_disk_page(dev)
File "./virtManager/details/details.py", line 2017, in _refresh_disk_page
self._addstorage.set_dev(disk)
File "./virtManager/device/addstorage.py", line 325, in set_dev
self.widget("disk-removable").set_active(removable)
TypeError: Argument 1 does not allow None as a value

---

I did not get this error with version 2.2.1 but get it again with version 3.1.0

Any advice?

Regards

Frank