diff --git a/includes/form.inc b/includes/form.inc
index 956f509..dca8f0c 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -1368,7 +1368,7 @@ function form_type_select_value($form, $edit = FALSE) {
  *   for this element. Return NULL to use the default.
  */
 function form_type_textarea_value($form, $edit = FALSE) {
-  if ($edit !== FALSE) {
+  if ($edit !== FALSE && $edit !== NULL) {
     // This should be a string, but allow other scalars since they might be
     // valid input in programmatic form submissions.
     return is_scalar($edit) ? (string) $edit : '';
@@ -1388,7 +1388,7 @@ function form_type_textarea_value($form, $edit = FALSE) {
  *   for this element. Return nothing to use the default.
  */
 function form_type_textfield_value($form, $edit = FALSE) {
-  if ($edit !== FALSE) {
+  if ($edit !== FALSE && $edit !== NULL) {
     // This should be a string, but allow other scalars since they might be
     // valid input in programmatic form submissions.
     if (!is_scalar($edit)) {
@@ -1411,8 +1411,8 @@ function form_type_textfield_value($form, $edit = FALSE) {
  *   for this element. Return nothing to use the default.
  */
 function form_type_token_value($form, $edit = FALSE) {
-  if ($edit !== FALSE) {
-    return (string)$edit;
+  if ($edit !== FALSE && $edit !== NULL) {
+    return (string) $edit;
   }
 }