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!
2010-07-28_114043

var self = this;
document.getElementById(“treegrid”).onclick = function(e) {
if(e.target.classList.contains(“showMenuClass”)){
self.contextMenu.showAt(e.target);
}
}

Unfortunaetly the problem cannot be reconstructed locally.
Please, refer to the following snippet. It seems to work well for me.
https://snippet.dhtmlx.com/iplpjzw1
If the problem still occur sfor you please, provide a complete demo or a similar snippet, where the problem could be reproduced.