diff --git a/modules/field_ui/field_ui.js b/modules/field_ui/field_ui.js
index 0a41c4c..7a49a4c 100644
--- a/modules/field_ui/field_ui.js
+++ b/modules/field_ui/field_ui.js
@@ -89,8 +89,7 @@ jQuery.fn.fieldUIPopulateOptions = function (options, selected) {
       var is_selected = ((typeof selected != 'undefined' && value == selected) || (typeof selected == 'undefined' && text == previousSelectedText));
       html += '<option value="' + value + '"' + (is_selected ? ' selected="selected"' : '') + '>' + text + '</option>';
     });
-
-    $(this).html(html).attr('disabled', disabled ? 'disabled' : '');
+    $(this).html(html).attr('disabled', disabled ? 'disabled' : false);
   });
 };