Trimming its initial gains, the Sensex at the Bombay Stock Exchange was trading 23 points in the positive territory at 19,659 in late morning deals, when reports last came in. The 30-share index had opened over 106 points in the green, on sustained buying by funds and retail investors amid a firm trend in other Asian bourses.The Nifty at the National Stock Exchange was trading 11 points in the positive zone at 5,951.