Do I need GtkBuildable?

[Martin Kalbfuß <ma kalbfuss web de>]

Hi again,

I designed an object based on gobject. I added it to an interface XML
file. When loading it, The object is created, and I can use it.

<interface>

  <object class="GtkListStore" id="list_model" >
    <columns>
      <column type="GdkPixbuf" />
      <column type="gchararray" />
      <column type="guint" />
      <column type="guint" />
    </columns>
  </object>

  <object class="BitmapList" id="bitmap_list" />

</interface>

While reading the docs, I found this:

In order to allow construction from a GtkBuilder UI description, an
object class must implement the GtkBuildable interface.

But I didn't do that. Is this an undocumented and correct behaviour, or
does it work by accident?

Thanks.