private void ActiveTheme_Changed(object sender, ActiveThemeChangedEventArgs e)
        {
            var value = e.Current;
            var old   = e.Previous;

            Child.ActiveTheme = value;
            if (value == null)
            {
                cmbTheme.SelectedIndex = (cmbTheme.Items.Count == 0) ? -1 : 0;
            }
            else if (cmbTheme.SelectedItem != value && cmbTheme.Items.Contains(value))
            {
                cmbTheme.SelectedItem = value;
            }
            UpdateDisplay(value, old);
        }
 private void ActiveTheme_Changed(object sender, ActiveThemeChangedEventArgs e)
 {
     var value = e.Current;
     var old = e.Previous;
     Child.ActiveTheme = value;
     if (value == null) {
         cmbTheme.SelectedIndex = (cmbTheme.Items.Count == 0) ? -1 : 0;
     } else if (cmbTheme.SelectedItem != value && cmbTheme.Items.Contains(value)) {
         cmbTheme.SelectedItem = value;
     }
     UpdateDisplay(value, old);
 }