<child>
<object class="GtkButton" id="up_button">
<property name="icon-name">list-add-symbolic</property>
+ <property name="halign">center</property>
+ <property name="valign">center</property>
<style>
<class name="circular"/>
</style>
<child>
<object class="GtkButton" id="down_button">
<property name="icon-name">list-remove-symbolic</property>
+ <property name="halign">center</property>
+ <property name="valign">center</property>
<style>
<class name="circular"/>
</style>