info.AddValue ("BackColor", BackColor);
info.AddValue ("ForeColor", ForeColor);
info.AddValue ("ImageKey", image_key);
- info.AddValue ("Group", group);
+ if (group != null)
+ info.AddValue ("Group", group);
if (sub_items.Count > 1) {
info.AddValue ("SubItemCount", sub_items.Count);
for (int i = 1; i < sub_items.Count; i++) {