diff --git a/unstable/xdg-shell/xdg-shell-unstable-v6.xml b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
index fc414851203453d26d5832afcc3f189fdd3e2faa..e4d552c687fe7ab19ca197d44203e5eac9f02315 100644
--- a/unstable/xdg-shell/xdg-shell-unstable-v6.xml
+++ b/unstable/xdg-shell/xdg-shell-unstable-v6.xml
@@ -171,7 +171,7 @@
 	xdg_popup is and how it is used.
       </description>
       <arg name="id" type="new_id" interface="zxdg_popup_v6"/>
-      <arg name="parent" type="object" interface="wl_surface"/>
+      <arg name="parent" type="object" interface="zxdg_surface_v6"/>
       <arg name="seat" type="object" interface="wl_seat" summary="the wl_seat of the user event"/>
       <arg name="serial" type="uint" summary="the serial of the user event"/>
       <arg name="x" type="int"/>