void AddChild(object item)
{
ModifiedItem modItem = (ModifiedItem)item;
Node newNode = (Node)Activator.CreateInstance(Type.GetType(modItem.newType));
modItem.node.AddChild(newNode);
ModifiedTreeLastFrame = true;
}
void ChangeNode(object item)
{
ModifiedItem modItem = (ModifiedItem)item;
Node newNode = (Node)Activator.CreateInstance(Type.GetType(modItem.newType));
//modItem.node = newNode; //not work, but why?
int index = modItem.node.parent.Children.IndexOf(modItem.node);
modItem.node.parent.Children[index] = newNode;
ModifiedTreeLastFrame = true;
}