Contextmenu showAt() problem on left click

Environment : DHTMLX Suite 7.0

I want to click left to show the contextMenu ,but it’s wrong position!

var self = this;
document.getElementById(“treegrid”).onclick = function(e) {

Unfortunaetly the problem cannot be reconstructed locally.
Please, refer to the following snippet. It seems to work well for me.
If the problem still occur sfor you please, provide a complete demo or a similar snippet, where the problem could be reproduced.