view object properties is not resetting on re-render of view in ember js

view variable is resetting on re-render of view but view object property not resetting on re-render of view

    App.FooviewView = Ember.View.extend({
        flag1:false,
        obj:{flag:false},
        actions:{
            test:function(){
                this.set('flag1',true)
                this.set('obj.flag1',true)
            }
        }
    })

on render of view flag1 is resetting to false but obj.flag is remains true. why is like that... help pls.