Enabling an additional screen in a Qubes OS Windows HVMI recently converted my work laptop over to using Qubes OS; an awesome OS based around the concept of using lightweight VMs to provide enhanced security.
Naturally I added a Windows VM using this handy guide http://www.qubes-os.org/doc/WindowsAppVms/ to install and configure a working Windows 7 install so i could run Powerpoint.
Everything worked great until i connected an external monitor; naturally my Qubes desktop expanded to fill the new monitor but my Windows VM was still stuck with a single display window. This is great but i needed a second window so i could view my presentation notes when doing a talk using the built in view in Powerpoint.
At first I thought maybe I could enable this through the ".conf" file for VM but couldn't find any option to enable emulation of an additional screen.
I tried assigning the video adapter hardware to the running VM but all that did was disable my laptop screen.
However I had success configuring it directly in the Windows VM.
- Connect up your external monitor to your system - Dom0 should detect and extend your desktop to this display.
- Boot your Windows VM and open the device hardware pane.
- Enable The "Standard VGA Graphics Adapter" and reboot the VM.
- Test that Powerpoint now detects your screen.
- Resize the new window through windows to make it usable
I highly recommend you give Qubes a go as it's a great idea with lots of advantages when you need to run lots of different applications and OS's on a single computer.