2006 tailgate lock

Hi, sorry if this has been posted before but I can't seem to find an answer to my specific problem.

When I go to open the tailgate, the window drops and stays there but it still doesn't open.
If I wind the window down fully, the tailgate opens no problem.
Could this just be a faulty sensor, tricking the car into thinking that the window hasn't moved down
Many thanks for any replies.

If the window drops, the door should unlock too. The lock motor is audible on mine - do you hear it when you squeeze the catch button? Or is it only audible when the window is wound down?

I hear the lock mechanism but it sounds like it opens then immediately locks again as im trying to open and stops on the latch but with the window in the down position, so then when I push the door up (fully closed) the window goes back up.
It's not catching on the latch, I put some grease on it to see where the catch goes and it looks good.
If I'm quick enough, I can swing the door open before it re-locks.
Is there some sort of switch in there that might be out of position?