diff --git a/xfce-base/garcon/metadata.xml b/xfce-base/garcon/metadata.xml
index 359901b31db49..c5e73dd639794 100644
--- a/xfce-base/garcon/metadata.xml
+++ b/xfce-base/garcon/metadata.xml
@@ -5,4 +5,8 @@
     <email>xfce@gentoo.org</email>
     <name>XFCE Team</name>
   </maintainer>
+  <use>
+    <flag name="gtk2">Build the garcon-gtk2-1 library (required
+      for <pkg>xfce-base/xfce4-panel</pkg> &lt; 4.13 only).</flag>
+  </use>
 </pkgmetadata>