Attaching a USB device to a AppVM fails silently

[juniorz]

Qubes OS version:

R4.0

Affected component(s):

---

Steps to reproduce the behavior:

1. Create a AppVM withouth qubes-usb-proxy
2. Start the AppVM
3. Connect a USB device
4. Use the "domains widget" to attach the USB device to the AppVM.

Expected behavior:

There should be an error message saying that qubes-usb-proxy is not installed on the target AppVM.
Ideally, there would be an actionable message that could be used to install qubes-usb-proxy if the user wants to.

Actual behavior:

The operation fails silently.

General notes:

---

Related issues:

[awokd]

Might be a regression of #3525 (comment)

[qubesos-bot]

Automated announcement from builder-github

The package qubes-desktop-linux-manager-4.0.9-1.fc25 has been pushed to the r4.0 testing repository for dom0.
To test this update, please install it with the following command:

sudo qubes-dom0-update --enablerepo=qubes-dom0-current-testing

Changes included in this update

[qubesos-bot]

Automated announcement from builder-github

The package qubes-desktop-linux-manager-4.0.9-1.fc25 has been pushed to the r4.0 stable repository for dom0.
To install this update, please use the standard update command:

sudo qubes-dom0-update

Or update dom0 via Qubes Manager.

Changes included in this update