diff --git a/NEWS b/NEWS
index f0d553b3..7ba715d6 100644
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,11 @@ NEWS ( CHANGELOG and HISTORY )                                     HTMLPurifier
     . Internal change
 ==========================
 
+ERRATA
+- PH5P is seriously broken here; it can result in fatal errors and exceptions. 
+  If you desire to use it, please use it with the latest, PHP5-only version of 
+  HTML Purifier.
+
 2.1.4, unknown release date
 ! DefinitionCacheFactory now can register new implementations
 ! CSS properties are now case-insensitive
@@ -19,6 +24,8 @@ NEWS ( CHANGELOG and HISTORY )                                     HTMLPurifier
 - Fix bug with trusted script handling in libxml versions later than 2.6.28.
 - Fix bug in comment parsing with DirectLex
 - Fix bug with rgb(0, 1, 2) color syntax with spaces inside shorthand syntax
+- HTMLPurifier_HTMLDefinition->addAttribute can now be called multiple times
+  on the same element without emitting errors.
 
 2.1.3, released 2007-11-05
 ! tests/multitest.php allows you to test multiple versions by running
diff --git a/library/HTMLPurifier/HTMLDefinition.php b/library/HTMLPurifier/HTMLDefinition.php
index e13e0c62..51367ca4 100644
--- a/library/HTMLPurifier/HTMLDefinition.php
+++ b/library/HTMLPurifier/HTMLDefinition.php
@@ -222,6 +222,8 @@ class HTMLPurifier_HTMLDefinition extends HTMLPurifier_Definition
     
     /**
      * Adds a custom attribute to a pre-existing element
+     * @note This is strictly convenience, and does not have a corresponding
+     *       method in HTMLPurifier_HTMLModule
      * @param $element_name String element name to add attribute to
      * @param $attr_name String name of attribute
      * @param $def Attribute definition, can be string or object, see
@@ -229,7 +231,11 @@ class HTMLPurifier_HTMLDefinition extends HTMLPurifier_Definition
      */
     function addAttribute($element_name, $attr_name, $def) {
         $module =& $this->getAnonymousModule();
-        $element =& $module->addBlankElement($element_name);
+        if (!isset($module->info[$element_name])) {
+            $element =& $module->addBlankElement($element_name);
+        } else {
+            $element =& $module->info[$element_name];
+        }
         $element->attr[$attr_name] = $def;
     }
     
diff --git a/tests/HTMLPurifier/HTMLDefinitionTest.php b/tests/HTMLPurifier/HTMLDefinitionTest.php
index 28fb28cc..e616f79e 100644
--- a/tests/HTMLPurifier/HTMLDefinitionTest.php
+++ b/tests/HTMLPurifier/HTMLDefinitionTest.php
@@ -87,6 +87,22 @@ a[href|title]
         
     }
     
+    function test_addAttribute_multiple() {
+        
+        $config = HTMLPurifier_Config::create(array(
+            'HTML.DefinitionID' => 'HTMLPurifier_HTMLDefinitionTest->test_addAttribute_multiple'
+        ));
+        $def =& $config->getHTMLDefinition(true);
+        $def->addAttribute('span', 'custom', 'Enum#attribute');
+        $def->addAttribute('span', 'foo', 'Text');
+        
+        $purifier = new HTMLPurifier($config);
+        $input = '<span custom="attribute" foo="asdf">Custom!</span>';
+        $output = $purifier->purify($input);
+        $this->assertIdentical($input, $output);
+        
+    }
+    
     function test_addElement() {
         
         $config = HTMLPurifier_Config::create(array(