close() function make window.open() lose focus

[yhnedison]

jquery-confirm version: v3.3.4

I'm submitting a ... (check one with "x") [x] bug report [ ] feature request [ ] support request

Current behavior:

Only happens in IE. Not in Chrome. In IE (11.615.17763.0),

var myAlert = $.confirm();
$.ajax(**some ajax call**).done(function(){
    window.open(**open a new window**);
    myAlert.close();
})

After new window pops up, it loses focus.

I tried to intentionally set

setTimeout(function(){
   myAlert.close();}, 3000)

It seems as long as close() get executed in parent page, it grabs the focus,

Only IE have this problem.

Expected behavior:

A new window should popup and get focused, and the alert message in original window should be closed Steps to reproduce:

Related code:

insert any relevant code here

Other information: