Lift gate shows that it is open but it is not. Interior lights remain on even though the lift gate is closed.

Update from May 21, 2017: It was the the back window that was open. It opens separately from the tailgate. It has an opener button on the remote and I must have hit it instead of the tailgate itself.

I did look look for a way to open the back window from in the car but could not find where that is possible. If anyone knows if there is a way to do that , please let me lknow.