RE: '88 S10 window problem
There should be a small nylon folding clip (folds like a book) that should be through the hole you mention. There are two of these-- one in the rear edge of the window at the top, the second is at the bottom front edge. They eventually fall part with age. If you don't replace both of them, the window will still fall off it's track. You can get aftermarket replacements at the auto parts store (I got mine at O'Reilly's, the brand was HELP). Putting both of them in will require removing the interior door panel. Not too hard-- easier if you buy a special pry tool for removing the hidden clips on the back of the door panel. Be prepared for some frustration getting the clips on and the window back into the track-- you have to intentionally take the window out of the track, and slant it so that the rear is high, front is low, to get the clips through the holes and secured.