I have a checkbox column that when checked / unchecked, causes the propertychanged event on the datasource to only fire once. If I submit the changes, then the event will fire again, but only once.

Am I missing something or shouldn't the event fire everytime a checkbox is checked/unchecked in the grid? Below is the event handler that I set up on the datasource's propertychanged event as well as the event declaration.

public MainPage()
{
  InitializeComponent();
  context.PropertyChanged += new System.ComponentModel.PropertyChangedEventHandler(context_PropertyChanged);
}

void context_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
    if (!context.IsLoading && !context.IsSubmitting && e.PropertyName.Equals("HasChanges"))
    {
        Row r = gridForecastSchedule.Rows[0];
        if (r != null)
        {
            HeaderCellControl hcc = (HeaderCellControl)((RowsManager)r.Manager).HeaderRow.Cells["Suppress"].Control;
            if (hcc != null)
            {
                CheckBox headerCB = hcc.Content as CheckBox;
                if (headerCB != null)
                {
                    headerCB.Checked -= All_Checked;
                    headerCB.Unchecked -= All_Checked;
                    headerCB.IsChecked = (context.ForecastScheduleWorkModels.Count() > 0 && context.ForecastScheduleWorkModels.Where(a => a.Suppress.Equals(false)).Count() == 0);
                    headerCB.Checked += new RoutedEventHandler(All_Checked);
                    headerCB.Unchecked += new RoutedEventHandler(All_Checked);
                }
            }
        }
    }

    if (context.HasChanges && (!context.IsLoading && !context.IsSubmitting))
        btnSave.IsEnabled = true;
    else
        btnSave.IsEnabled = false;

    if (context.IsSubmitting)
    {
        busyDialog.IsBusy = true;
    }
}