XPS 2720 - Video input source

Hi All, I am new to this forum. I just recently purchased an XPS 2720, Intel I7, 2 TB, 32GB SSD, pretty much loaded. What interested me was the HDMI input into the XPS 27. In the past I used Windows Media Center on an XPS mini tower with a tv tuner to receive live tv broadcast. Well, I connected my Verizon FIOS Arris IPC1100 media server to the HDMI input port on the XPS and I get all my cable channels via the Set top box when I change the video input on the OSD to HDMI. But I cannot access the desktop unless I change the OSD back to the Computer input. So I have been trolling the web to find out the answer to my question for days to no avail. The question is can I simultaneously watch my live tv broadcast from the HDMI input while working on my desktop. I would think there could be  an application for a picture in picture window where I can specify the HDMI input and voila', I would have a window on my desktop with TV. So can anyone please tell me if this is possible or if not what alternatives are available. Thanks.