Silverlight 4: Property not refreshing by INotify

Question

HI ,

I am going to upgrade our applicaiton from silverlight 3 to silerlight 4. and also from telerik 2009 to 2010 (Which supports silverlight version 4).

There is one strange problem is coming.

I have one property like

public ObservableCollection<FunctionalityDto> CurrentActivities
    {
        get
        {
            if (currentActivities == null || currentActivities.Count == 0)
            {

            }
            return currentActivities;
        }
        set
        {
            currentActivities = value;
            this.OnPropertyChanged("CurrentActivities");
        }
    }

As and when i am going to assign null value to the "CurrentActivities" then it calls Set method but not calling to get method after assigning null value.

It is working fine with previous version of silverlight.

Not able to figure out what is the actual problem.

Can anyone have any idea about same?

Please revert back....

THanks, Bhushan