I have a 2001 ML320 that I purchased in April. I just started noticing this goop on glass near the rear edge of the sun roof. It is perpendicular to the rear edge and centered and occurs either as you open the sun roof or upon closing it. I cleaned it off and then it reappeared after closing my sun roof. I also noticed a clicking sound and some resistence when I try to close the interior cover / shield for the sun roof. All is this is new. Any suggestions?