Index: modules/block/block.admin.inc
===================================================================
--- modules/block/block.admin.inc	(revision 210)
+++ modules/block/block.admin.inc	(working copy)
@@ -69,7 +69,7 @@
     $form[$key]['weight'] = array(
       '#type' => 'weight',
       '#default_value' => $block['weight'],
-      '#delta' => $weight_delta,
+      '#delta' => ($weight_delta === (float) 1 ? 999 : $weight_delta),
     );
     $form[$key]['region'] = array(
       '#type' => 'select',