mydialog.ui

<interface>
  <template class="MyDialog" parent="GtkDialog">
    <child type="action">
      <object class="GtkButton" id="cancel_button">
        <property name="visible">True</property>
        <property name="label">_Abort</property>
        <property name="use_underline">True</property>
      </object>
    </child>
    <child type="action">
      <object class="GtkButton" id="go_button">
        <property name="visible">True</property>
        <property name="label">_Go</property>
        <property name="use_underline">True</property>
        <property name="can_default">True</property>
      </object>
    </child>
    <action-widgets>
      <action-widget response="cancel">cancel_button</action-widget>
      <action-widget response="apply" default="True">go_button</action-widget>
    </action-widgets>
  </template>
</interface>