private void DialogRemoveCollection_DialogCompleted(object sender, DialogButtonClickedEventArgs e)
{
if (e.DialogResult == DialogResult.OK)
{
TileManagerViewModel vm = DataContext as TileManagerViewModel;
CollectionSet selectedCollection = vm.SelectedCollection;
selectedCollection.Delete();
vm.LoadedCollections.Remove(selectedCollection);
vm.SelectedCollection = null;
}
}