--- includes/common.inc?rev=1.431	2005-03-28 18:27:01.000000000 +0200
+++ includes/common.inc	2005-03-28 18:28:09.000000000 +0200
@@ -413,6 +413,20 @@ function fix_gpc_magic() {
   }
 }
 
+function _fix_checkboxes($key) {
+  if (empty($_POST['edit'][$key])) {
+    $_POST['edit'][$key] = array();
+  }
+}
+
+function fix_checkboxes() {
+  static $fixed = false;
+  if (!$fixed && array_key_exists('edit', $_POST) && array_key_exists('_form_checkboxes', $_POST['edit'])) {
+    array_map('_fix_checkboxes', $_POST['edit']['_form_checkboxes']);
+    $fixed = true;
+  }
+}
+
 /**
  * @name Conversion
  * @{
@@ -1182,9 +1196,8 @@ function form_checkboxes($title, $name, 
       $choices .= '<label class="option"><input type="checkbox" class="form-checkbox" name="edit['. $name .'][]" value="'. $key .'"'. (in_array($key, $values) ? ' checked="checked"' : ''). drupal_attributes($attributes) .' /> '. $choice .'</label><br />';
     }
     // Note: because unchecked boxes are not included in the POST data, we
-    // include a form_hidden() which will be overwritten as soon as there is at
-    // least one checked box.
-    return form_hidden($name, 0) . theme('form_element', $title, $choices, $description, NULL, $required, _form_get_error($name));
+    // indicate that $name is a form_checkbox.
+    return form_hidden($name, 0). form_hidden('_form_checkboxes][', $name). theme('form_element', $title, $choices, $description, NULL, $required, _form_get_error($name));
   }
 }
 
--- index.php?rev=1.82	2005-03-28 18:28:46.000000000 +0200
+++ index.php	2005-03-28 18:23:17.000000000 +0200
@@ -14,6 +14,7 @@
 include_once 'includes/common.inc';
 
 fix_gpc_magic();
+fix_checkboxes();
 
 $status = menu_execute_active_handler();
 switch ($status) {