diff --git a/src/x11/xprops.c b/src/x11/xprops.c
index 729d5b684..1b97b2648 100644
--- a/src/x11/xprops.c
+++ b/src/x11/xprops.c
@@ -958,6 +958,8 @@ meta_prop_get_values (MetaX11Display *x11_display,
           goto next;
         }
 
+      values[i].source_xwindow = xwindow;
+
       switch (values[i].type)
         {
         case META_PROP_VALUE_INVALID:
diff --git a/src/x11/xprops.h b/src/x11/xprops.h
index b8d723f07..f55d80baa 100644
--- a/src/x11/xprops.h
+++ b/src/x11/xprops.h
@@ -132,6 +132,7 @@ typedef struct
   MetaPropValueType type;
   Atom atom;
   Atom required_type; /* autofilled if None */
+  Window source_xwindow;
 
   union
   {