Automatic template update creating issues

Hi Everyone, I am new to ember and I have implemented ember polling in my project for dynamic update and automatic refresh of UI. As soon as I implemented polling, I started facing one issue related to checkbox that I have used to perform certain task for that I have used itemController. So when I click on checkbox to perform certain event, Polling automatically updates the whole template in which my check box is present and as a result of that I am not able not perform the the desired action.

Handlebar File:

 {{#each app in container.applications itemController="app"}}
       <div> {{input type="checkbox" checked=app.isCompleted }} </div>
 {{/each}}

JS File

CCM_ROOT.AppController = Ember.ObjectController.extend({
needs:['homeTemplate'],
isCompleted: function(key, value){
	var model = this.get('model');

	if (value === undefined) 
	{
		var isSelected=model.get('isSelected');
		if(isSelected === undefined)
			isSelected = false;
		
		return isSelected;
	} 
	else 
	{
		
		this.get('controllers.homeTemplate').handleSelectedApplication(value, model);
		return value;
	}
		
}.property('model.isCompleted'),

});

}.property('model.isCompleted'), does not seem right . Perhaps demo the problem on http://ember-twiddle.com/