I followed the example and the problem occurred when scolling the position of the shadow of the task will be different from the position of the mouse cursor.
Hi @linhtv97,
This issue occurred because this implementation doesn’t calculate the scroll position. In order to fix it, you should change your y-position calculation, like in this code fragment:
var y_pos;
var sPos;
var posY;
gantt.attachEvent("onMouseMove", function (id,e){
sPos = gantt.getScrollState();
posY = sPos.y;
y_pos = e.clientY + posY;
});