diff --git a/gdk/gdktoplevel.c b/gdk/gdktoplevel.c
index 3b8a22a611..a7802a3504 100644
--- a/gdk/gdktoplevel.c
+++ b/gdk/gdktoplevel.c
@@ -99,6 +99,7 @@ gdk_toplevel_notify_compute_size (GdkToplevel     *toplevel,
                                   GdkToplevelSize *size)
 {
   g_signal_emit (toplevel, signals[COMPUTE_SIZE], 0, size);
+  gdk_toplevel_size_validate (size);
 }
 
 static void
diff --git a/gdk/gdktoplevelsize.c b/gdk/gdktoplevelsize.c
index 18933523ff..276e63f951 100644
--- a/gdk/gdktoplevelsize.c
+++ b/gdk/gdktoplevelsize.c
@@ -117,3 +117,19 @@ gdk_toplevel_size_set_min_size (GdkToplevelSize *size,
   size->min_width = min_width;
   size->min_height = min_height;
 }
+
+void
+gdk_toplevel_size_validate (GdkToplevelSize *size)
+{
+  if (size->min_width > size->bounds_width ||
+      size->min_height > size->bounds_height)
+    g_warning ("GdkToplevelSize: min_size exceeds bounds");
+
+  if (size->width > size->bounds_width ||
+      size->height > size->bounds_height)
+    g_warning ("GdkToplevelSize: size exceeds bounds");
+
+  if (size->min_width > size->width ||
+      size->min_height > size->height)
+    g_warning ("GdkToplevelSize: min_size exceeds size");
+}
diff --git a/gdk/gdktoplevelsizeprivate.h b/gdk/gdktoplevelsizeprivate.h
index eaddefba0b..3576513888 100644
--- a/gdk/gdktoplevelsizeprivate.h
+++ b/gdk/gdktoplevelsizeprivate.h
@@ -36,4 +36,6 @@ void gdk_toplevel_size_init (GdkToplevelSize *size,
                              int              bounds_width,
                              int              bounds_height);
 
+void gdk_toplevel_size_validate (GdkToplevelSize *size);
+
 #endif /* __GDK_TOPLEVEL_SIZE_PRIVATE_H__ */