Index: django/contrib/admin/media/js/SelectBox.js
===================================================================
--- django/contrib/admin/media/js/SelectBox.js  (revision 4123)
+++ django/contrib/admin/media/js/SelectBox.js  (working copy)
@@ -11,14 +11,21 @@
     },
     redisplay: function(id) {
         // Repopulate HTML select box from cache
+       // Remove the box from the DOM, manipulate it, then insert again
+       // (offline DOM manipulation = better performance)
         var box = document.getElementById(id);
+       var parent = box.parentNode;
+       var nextSibling = box.nextSibling; // remember where the node was
+       parent.removeChild(box);
         box.options.length = 0; // clear all options
-        for (var i = 0, j = SelectBox.cache[id].length; i < j; i++) {
-            var node = SelectBox.cache[id][i];
+       var cache = SelectBox.cache[id];
+        for (var i = 0, j = cache.length; i < j; i++) {
+            var node = cache[i];
             if (node.displayed) {
                 box.options[box.options.length] = new Option(node.text, node.value, false, false);
             }
         }
+       parent.insertBefore(box,nextSibling); // insert back in place
     },
     filter: function(id, text) {
         // Redisplay the HTML select box, displaying only the choices containing ALL