Mumbai, Nov 9 (UNI) Bollywood megastar Amitabh Bachchan on Sunday greeted fans gathered outside his Juhu residence, Jalsa, from behind a protective glass enclosure, amid heightened security concerns following recent threats and a reported shooting incident in the locality. The unusual security arrangement was noticed during Bachchan's customary Sunday appearance outside his bungalow, where hundreds of fans traditionally gather to catch a glimpse of the veteran actor. The protective glass panels, which appeared to cover three sides of the wheeled platform on which Bachchan usually stands while greeting his admirers, were first noticed during his November 1 appearance. The development…