Fix an issue where nested fieldgroups get misplaced when nested 3 groups deep or more.

This solution uses a referenced single-depth array so that the nested group can be easily and properly placed into the appropriate parent group.

diff -Nurp ../cck.orig/includes/content.admin.inc ./includes/content.admin.inc
--- ../cck.orig/includes/content.admin.inc	2010-06-02 16:15:54.000000000 -0500
+++ ./includes/content.admin.inc	2010-06-02 16:16:24.000000000 -0500
@@ -1687,10 +1687,17 @@ function _content_overview_order(&$form,
   // Nested fieldgroup
   if (module_exists('fieldgroup')) {
     // readjust the depth and parenting of fieldgroup
+    $nested = array();
     foreach ($group_rows as $name) {
       if ($parent = $form[$name]['parent']['#value']) {
         $form[$name]['#depth'] = $form[$parent]['#depth'] + 1;
-        $dummy[$parent][$name] = $dummy[$name];
+        if (array_key_exists($parent, $nested)){
+          $nested[$parent][$name] = $dummy[$name];
+          $nested[$name] = & $nested[$parent][$name];
+        } else {
+          $dummy[$parent][$name] = $dummy[$name];
+          $nested[$name] = & $dummy[$parent][$name];
+        }
         unset($dummy[$name]);
       }
     }