Normally, a GtkAboutDialog is shown using the convenience
API. But if you manually construct one and show it by calling
gtk_widget_show_all() on it, the license tab would show up
uninvited. Fix that.
https://bugzilla.gnome.org/show_bug.cgi?id=724411
<child>
<object class="GtkBox" id="credits_page">
<property name="visible">False</property>
+ <property name="no-show-all">True</property>
<property name="can_focus">False</property>
<property name="orientation">vertical</property>
<property name="spacing">8</property>
<child>
<object class="GtkBox" id="license_page">
<property name="visible">False</property>
+ <property name="no-show-all">True</property>
<property name="can_focus">False</property>
<property name="orientation">vertical</property>
<property name="spacing">8</property>