// Press Ctrl key to merge
$(document).keydown(function (e) {
                if (e.keyCode === 17) {
                    spread.options.allowUserDragMerge = true;
                }
            });
            $(document).keyup(function (e) {
                if (e.keyCode === 17) {
                    spread.options.allowUserDragMerge = false;
                }
            });

activeSheet.bind(GC.Spread.Sheets.Events.DragMerging, function (e, data) {
var mergeRange = data.mergeRange;
alert(mergeRange.row);   
            });

activeSheet.bind(GC.Spread.Sheets.Events.DragMerged, function (e, data) {
var mergeRange = data.mergeRange;
alert(mergeRange.row);   
            });