dat.GUI doesn't update when I change the object

Question

Description of the problem:

There are 2 variable:

controller1 = {i: 100};
controller2 = {i: 300};

and a control variable

control = controller1;

I attached dat.GUI to control.i.

gui = new dat.GUI();
controller = gui.add(control, "i");
controller.listen();

So it displays the value of controller1.i and when I change value in dat.GUI, it changes value of controller1.i.

After that, I run:

control = controller2;

When I change the value in dat.GUI, I want it to change controller2.i, but right now it changes controller1.i.

Here is the pen: http://codepen.io/kranzy/pen/QKzYAW

or Stack Snippets:

controller1 = {i: 100};
controller2 = {i: 300};
control = controller1;
click.addEventListener("click", function() {
  control = control == controller1 ? controller2:controller1;
});
gui = new dat.GUI();
controller = gui.add(control, "i");
controller.listen();
setInterval(function (){
  current.textContent = JSON.stringify(control);
  x.textContent = JSON.stringify(controller1);
  y.textContent = JSON.stringify(controller2);
},1000/24)

<script src="https://cdnjs.cloudflare.com/ajax/libs/dat-gui/0.6.1/dat.gui.min.js"></script>
<h1>Controller 1: <code id="x"></code></h1>
<h1>Controller 2: <code id="y"></code></h1>
<button id="click"><h1>Change controller</h1></button>
<h1>Value of current controller: <code id="current"></code></h1>

The only way I can see is deleting the controller and init it again everytime I change control variable, but I want to know another way.
That way is suggested here: Refreshing dat.gui variable (not really the same as my question, but related).
If you don't know anything about dat.GUI, you can take the tour here and see if you can help me.

Answer 1

I was stupid... It's as easy as hell:

click.addEventListener("click", function() {
  control = control == controller1 ? controller2:controller1;
  controller.object = control;
  // change the internal reference in dat.GUI
});

I found that way after inspecting the dat.GUI object.

Test case: http://codepen.io/anon/pen/aBvvmV