A couple weeks after I picked up my Air, I had a similar issue with the window only closing half-way after being opened.
After a few frustrating minutes, I figured out I could get the window fully closed by pulling the window up and jiggling it while also holding the window close button. Once the window is about 2/3 closed, I physically let go of the window and let the motor finish closing it. When I was able to get a mobile tech to look at it, he said he just had to clean and re-lube the rails and the window has been working perfectly fine since then.
Not sure if this same issue affects the Gravity, but I bet it's a relatively simple fix. The hard part is getting the appointment.