private void _rootPanel_ChildrenTreeChanged(object sender, ChildrenTreeChangedEventArgs e)
 {
     RaisePropertyChanged("IsSinglePane");
     RaisePropertyChanged("SinglePane");
 }
 private void _rootPanel_ChildrenTreeChanged(object sender, ChildrenTreeChangedEventArgs e)
 {
     RaisePropertyChanged("IsSinglePane");
     RaisePropertyChanged("SinglePane");
 }