private void Button_Click(object sender, RoutedEventArgs e)
        {
            Tasks.Show.Models.Folder f = this.DataContext as Tasks.Show.Models.Folder;

            if (f != null)
            {
                bool hasItems = App.Root.TaskData.Tasks.Any(t => t.Folder == f);
                if (!hasItems)
                {
                    App.Root.TaskData.RemoveFolder(f);
                }
            }
        }
        private void Popup_Opened(object sender, EventArgs e)
        {
            ColorListBox.SelectedItem = null;
            m_newFolderTextBox.Text   = Folder == null ? "" : Folder.Name;
            m_newFolderTextBox.Focus();
            m_newFolderTextBox.SelectAll();

            // only show the remove button if the folder is empty

            Tasks.Show.Models.Folder f = this.DataContext as Tasks.Show.Models.Folder;

            if (f != null)
            {
                bool hasItems = App.Root.TaskData.Tasks.Any(t => t.Folder == f);
                if (!hasItems)
                {
                    RemoveButtonGrid.Visibility = Visibility.Visible;
                }
                else
                {
                    RemoveButtonGrid.Visibility = Visibility.Collapsed;
                }
            }
        }