Not able to insert item(smart)

In the synfig wiki, the basic tutorial, the last one is an animation of a growing plant, in that tutorial it says to insert item(smart) but when I am doing it it only says "remove item(smart) and when I click on it, it removes a vertex of my plant

In short, I am unable to insert item(smart)

Help please

Can you elaborate? How exactly you do it? You supposed to right-click on the dotted line or on orange vertex.