because it happened in my 190e. All you need to do is rotate the white guide 180 degrees from the sheet metal piece behind it. I can't remember CCW or CW. Go with the direction that extend the window travel your missing 1-2 inches. It will take some force to rotate and you have to slightly pry the metal plate to allow the plastic guide to rotate. Good Luck.
Meza

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Meza
1993 190E 2.6
Advanced Diesel Systems Test and Research Engineer