Index: modules/system/system.css
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.css,v
retrieving revision 1.16
diff -u -r1.16 system.css
--- modules/system/system.css	30 Nov 2006 01:55:31 -0000	1.16
+++ modules/system/system.css	5 Dec 2006 15:08:33 -0000
@@ -325,6 +325,14 @@
 html.js fieldset.collapsible legend a {
   display: block;
 }
+/* Avoid jumping around due to margins collapsing into collapsible fieldset border */
+html.js fieldset.collapsible div {
+  overflow: auto;
+}
+/* Make sure overflow behavior attaches only to top-level wrapper div in fieldset */
+html.js fieldset.collapsible div div {
+  overflow: visible;
+}
 
 /*
 ** Resizable text areas
Index: misc/collapse.js
===================================================================
RCS file: /cvs/drupal/drupal/misc/collapse.js,v
retrieving revision 1.8
diff -u -r1.8 collapse.js
--- misc/collapse.js	17 Nov 2006 20:36:46 -0000	1.8
+++ misc/collapse.js	5 Dec 2006 15:08:32 -0000
@@ -66,8 +66,6 @@
       $(div2).append(el);
       el = next;
     }
-    // Avoid jumping around due to margins collapsing into fieldset border
-    $(div1).css('overflow', 'hidden');
 
     // Expand if there are errors inside
     if ($('input.error, textarea.error, select.error', this.parentNode).size() > 0) {