diff --git a/gtk/ui/gtktooltipwindow.ui b/gtk/ui/gtktooltipwindow.ui
index 2cecd58c73..d0fc9bc1c6 100644
--- a/gtk/ui/gtktooltipwindow.ui
+++ b/gtk/ui/gtktooltipwindow.ui
@@ -13,6 +13,7 @@
         </child>
         <child>
           <object class="GtkLabel" id="label">
+            <property name="hexpand">1</property>
             <property name="wrap">1</property>
             <property name="max-width-chars">50</property>
           </object>