diff -ruaN gtkmdi.orig/mdi.c gtkmdi/mdi.c
--- gtkmdi.orig/mdi.c	2002-08-22 12:34:39.000000000 +0300
+++ gtkmdi/mdi.c	2002-12-05 09:40:09.000000000 +0200
@@ -374,7 +374,9 @@
   g_return_if_fail (GTK_IS_MDI (mdi));
 
   children = mdi->children;
-  n = g_list_length (children);
+if (( n = g_list_length (children)) == 0 ) {
+return;
+}
   width = GTK_WIDGET (mdi)->allocation.width;
   height = GTK_WIDGET (mdi)->allocation.height / n;
   for (i = 0; i < n; i++)