[AC-5979] iOS 12 - TabGroup.activeTab.openWindow opens window blank

'use strict';
function createWindow() {
  var win = Ti.UI.createWindow();

  function getRandomColor() {
    var letters = '0123456789ABCDEF';
    var color = '#';
    for (var i = 0; i < 6; i++) {
      color += letters[Math.floor(Math.random() * 16)];
    }
    return color;
  }
  function rand() {
    return Math.floor(Math.random() * 10);
  }
  function createRow(i) {
    var r = Ti.UI.createTableViewRow({
      backgroundColor: getRandomColor(),
      height: 50
    });
    var l = Ti.UI.createLabel({
      text: 'Loading...' + i,
      left: 0
    });
    r.add(l);
    r.go = function() {
      setTimeout(function() {
        l.text = 'Loaded ' + i;
        //r.backgroundColor = getRandomColor();
        l.animate({
          duration: 500,
          autoreverse: true,
          repeat: 5,
          left: 250
        });
      }, rand() * 200);
    };
    return r;
  }
  var rows = [];
  for (var i = 0; i < 10000; i++) {
    rows.push(createRow(i));
  }

  function createSection() {
    var s = Ti.UI.createTableViewSection();
    rows.forEach(r => {
      s.add(r);
      setTimeout(function() {
        r.go();
      }, 0);
    });
    return s;
  }

  var table = Ti.UI.createTableView({
    data: [createSection()]
  });

  win.add(table);
  return win;
}

function createTabGroup() {
  var tabs = ['blue', 'red', 'green', 'yellow'].map(function(c) {
    var win = Ti.UI.createWindow({
      backgroundColor: c,
      title: c
    });
    win.add(Ti.UI.createLabel({ text: 'I am a' + c + ' window.' }));
    win.addEventListener('click', openTab);

    var tab = Ti.UI.createTab({
      window: win,
      title: c
    });
    return tab;
  });
  var tabGroup = Ti.UI.createTabGroup({
    tabs: tabs
  });
  return tabGroup;
}
var tabGroup = createTabGroup();

let win;
function openTab() {
  //if (win) { tabGroup.activeTab.close(win); }
  win = createWindow();
  tabGroup.activeTab.open(win);
}
setInterval(openTab, 3000);

tabGroup.open();