diff --git a/gtk/ui/gtkdialog.ui b/gtk/ui/gtkdialog.ui
index 76cbe1675e..89d162f655 100644
--- a/gtk/ui/gtkdialog.ui
+++ b/gtk/ui/gtkdialog.ui
@@ -11,7 +11,9 @@
           <class name="dialog-vbox"/>
         </style>
         <child>
-          <object class="GtkBox" id="content_area"/>
+          <object class="GtkBox" id="content_area">
+            <property name="orientation">1</property>
+          </object>
         </child>
         <child>
           <object class="GtkBox" id="action_box">