backbone coffeescript inheritance issue

Standard fiddle

by mwagner72

HTML

<script src="http://ajax.cdnjs.com/ajax/libs/underscore.js/1.1.4/underscore-min.js"></script>
<script src="http://ajax.cdnjs.com/ajax/libs/backbone.js/0.3.3/backbone-min.js"></script>
<script src="https://raw.github.com/theSociableme/jsfiddlefiles/master/base_class.js"></script>
<script src="https://raw.github.com/theSociableme/jsfiddlefiles/master/myapp.js"></script>

CoffeeScript

class Page extends MyApp.Models.BaseClass

    initialize: () ->
        console.log('Page Object initialized')
        @._dirty = false
        @changes = []
        @.name = 'Page'
        #@editView = new RequestBuilder.Views.Shared.EditView(el: '#off-screen-loader', model: @)
        @._linked = false
    url: () ->
        '/pages/' + @id
        
p = new Page();

        
console.log p.isDirty()

p.Dirty();  
      
console.log p.isDirty()