/// <summary>
        /// Close the others pop up when the user click on a Multicombobox
        /// </summary>
        private void Mscbx_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            MultiSelectComboBox mscbx = (MultiSelectComboBox)sender;

            // Don't close the popup if the MultiSelectComboBox selected is open
            if ((bool)mscbx.MultiSelectCombox.Tag != true)
            {
                CloseAllPopup();
            }
        }
        /// <summary>
        /// Update the elements in the control when the ItemsSource property is modified
        /// </summary>
        private static void OnItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            MultiSelectComboBox control = (MultiSelectComboBox)d;

            control.LoadElementsToControl();
        }