private void AddButton_Click(object sender, EventArgs e) { List <SongEntry> selected = (from SongEntry s in SongList.SelectedItems select s).ToList(); List <string> path = PathToSelectedGroup(); TreeNode group = GroupList.SelectedNode; if (group.ForeColor != Color.RoyalBlue) { group = group.Parent; } GroupList.BeginUpdate(); SongList.BeginUpdate(); foreach (var s in selected) { Metadata.AddSongToGroup(path, s.UniqueId); AddTreeViewSong(group, s); SongList.Items.Remove(s); } GroupList.EndUpdate(); SongList.EndUpdate(); MadeChanges = true; }