AirParrot 2 does not enable desktop extension for Windows at this time, but there is a trick for Windows 10 users that will allow this. Unfortunately, this requires that you only have 1 physical monitor connected to your computer and that your video card is powerful enough to render an artificial display.
Windows 10 users:
- Press the Windows Key and type "Project"
- Choose the "Project To a Second Screen" option that appears in your search
- A bar will open on the right side of your screen. Choose the option labeled Extend
Close the sidebar and now launch AirParrot. Once AirParrot loads, select Display 2 in the "From" section of the AirParrot menu, and then select the AppleTV to start mirroring. You will now have a desktop extension on your AppleTV.
Please note that this is a workaround and changing system preferences isn't something we recommend or support.