Microsoft has a firm grip on the handheld software market, winning the lead in shipments for the first time, a new report from Gartner shows. Shipments of handhelds that use Microsoft’s Windows CE operating system rose by about 33 percent to about 1.4 million in the third quarter, compared with the same period last year. Meanwhile, shipments of handhelds that use the Palm operating system shrank by 26 percent to 851,000.