qx mixin initialization error

gistfile1.txt

qx.Class.define("MyClass", {
  extend: qx.core.Object,
  
  include: [qx.ui.core.MBlocker],

  construct: function () {
    this.base(arguments);
    this.setBlockerColor("#D5D5D5"); // method from mixin
    this.setBlockerOpacity(0.5); // method from mixin
  }
});

var instance = new MyClass(); // throws error because qx.ui.core.MBlocker.construct will be called AFTER MyClass.construct