It would help to know what the panel looks like now to see what needs to be done. I loved those movable panels on my 2003, and only once did the holding hook pop out of the slot, so the panel opened more.
I can look later to be sure, but I think the bottom part of that panel snaps onto a receiving bar on the bottom of the door panel.
I can look later to be sure, but I think the bottom part of that panel snaps onto a receiving bar on the bottom of the door panel.