update of reactive var

gistfile1.txt

https://github.com/jagi/meteor-astronomy-examples/blob/flowrouter/

On the repo above on the collections.js file I did  the following:
...
Users = new Mongo.Collection('users');

Users.allow({
  update: function() { return true; }
});

Users.deny({
  update: function() { return false; }
});
...

Then on I put a console.log on line 25.

---
Template.UserForm.onCreated(function() {
  var _id = FlowRouter.getParam('_id');

  if (_id) {
    this.subscribe('user', _id);
    var user = Users.findOne(_id);
    console.log(user);
    this.data.user = new ReactiveVar(user);
  } else {
    this.data.user = ReactiveVar(new User());
  }
});
---

I run the application, I create a user and I go to the edit route.

The user now can be seen on browser console (due to console.log of line 25)

I store it on global variable temp1 (with right click of mouse on the logged User class instance)
I do:
temp1.set('firstName', 'whatever');
and the input does not change the text to whatever
When I do:
temp1.save()
It does not update the input.

How can a reactive var make the template to be re-render?

thank you