diff --git a/src/wayland/meta-wayland-subsurface.c b/src/wayland/meta-wayland-subsurface.c
index 4055e6882..3e088b04f 100644
--- a/src/wayland/meta-wayland-subsurface.c
+++ b/src/wayland/meta-wayland-subsurface.c
@@ -102,7 +102,7 @@ static gboolean
 is_sibling (MetaWaylandSurface *surface,
             MetaWaylandSurface *sibling)
 {
-  return surface->sub.parent == sibling->sub.parent;
+  return surface != sibling && surface->sub.parent == sibling->sub.parent;
 }
 
 static gboolean