This example is still using a GtkVBox, and it happened to be broken
by gtk-builder-tool simplify.
</object>
</child>
</object>
+ <packing>
+ <property name="expand">0</property>
+ </packing>
</child>
<child>
<object class="GtkToolbar" id="toolbar1">
</child>
</object>
<packing>
+ <property name="expand">0</property>
<property name="position">1</property>
</packing>
</child>
</object>
<packing>
<property name="position">3</property>
+ <property name="expand">0</property>
</packing>
</child>
</object>