=== modified file addons/openerp/static/javascript/form_state.js
--- addons/openerp/static/javascript/form_state.js	2011-01-19 00:54:20 +0000
+++ addons/openerp/static/javascript/form_state.js	2011-02-14 18:40:12 +0000
@@ -170,7 +170,7 @@
     for (var i = 0; i < expr.length; i++) {
 
         var ex = expr[i];
-        var elem;
+        var elem = null;
         if (ref_elem.parents('table.grid').length) {
             var parent = ref_elem.parents('tr.grid-row');
             elem = parent.find(idSelector(prefix + ex[0]));