Glade: adding a widget to a toolitem

When i try to add a widget to a toolitem, Glade says i need to add a placeholder. Where can i find this placeholder ? I thought a toolitem was a placeholder.

Again, i had to modify the xml file.

Just add

    <child>
        <placeholder/>
    <child>

inside the GtkToolItem

Oh my Gladys :upside_down_face: