Your missing a piece of U channel that the window manufacturer glues to the glass. You can buy a small piece of U channel one side attaches to glass the other side You will have to cut the side off leaving only two pieces sticking up for the latches to grab line it up and use J B weld 2 part epoxy to attach to glass. I've been lucky I had to reattach mine an 1 of my crank out windows, the 2 arms that push the window in and out are attached to a piece of metal thats glued to the glass the same way. I called the glass company, they said they only sell all new glass with metal channels attached, no parts and very expensive. A piece of aluminum channel is probably $5 and J B Weld $10.