diff --git a/NEWS b/NEWS
index 6bc8a962..90497358 100644
--- a/NEWS
+++ b/NEWS
@@ -16,6 +16,8 @@ NEWS ( CHANGELOG and HISTORY )                                     HTMLPurifier
   did nothing.  Thanks David Rothstein for reporting.
 ! Add documentation about configuration directive types.
 ! Add %CSS.ForbiddenProperties configuration directive.
+! Add %HTML.FlashAllowFullScreen to permit embedded Flash objects
+  to utilize full-screen mode.
 - Fix improper handling of Internet Explorer conditional comments
   by parser.  Thanks zmonteca for reporting.
 - Fix missing attributes bug when running on Mac Snow Leopard and APC.
diff --git a/configdoc/usage.xml b/configdoc/usage.xml
index 4086092d..a8c465db 100644
--- a/configdoc/usage.xml
+++ b/configdoc/usage.xml
@@ -347,6 +347,11 @@
    <line>13</line>
   </file>
  </directive>
+ <directive id="HTML.FlashAllowFullScreen">
+  <file name="HTMLPurifier/AttrTransform/SafeParam.php">
+   <line>37</line>
+  </file>
+ </directive>
  <directive id="Core.EscapeInvalidChildren">
   <file name="HTMLPurifier/ChildDef/Required.php">
    <line>62</line>
diff --git a/library/HTMLPurifier/AttrTransform/SafeParam.php b/library/HTMLPurifier/AttrTransform/SafeParam.php
index 3f992ec3..d378c4f5 100644
--- a/library/HTMLPurifier/AttrTransform/SafeParam.php
+++ b/library/HTMLPurifier/AttrTransform/SafeParam.php
@@ -33,6 +33,13 @@ class HTMLPurifier_AttrTransform_SafeParam extends HTMLPurifier_AttrTransform
             case 'allowNetworking':
                 $attr['value'] = 'internal';
                 break;
+            case 'allowFullScreen':
+                if ($config->get('HTML.FlashAllowFullScreen')) {
+                    $attr['value'] = ($attr['value'] == 'true') ? 'true' : 'false';
+                } else {
+                    $attr['value'] = 'false';
+                }
+                break;
             case 'wmode':
                 $attr['value'] = 'window';
                 break;
diff --git a/library/HTMLPurifier/ConfigSchema/schema.ser b/library/HTMLPurifier/ConfigSchema/schema.ser
index 20bd89df..2d7cfa1a 100644
Binary files a/library/HTMLPurifier/ConfigSchema/schema.ser and b/library/HTMLPurifier/ConfigSchema/schema.ser differ
diff --git a/library/HTMLPurifier/ConfigSchema/schema/Filter.YouTube.txt b/library/HTMLPurifier/ConfigSchema/schema/Filter.YouTube.txt
index 7fa6536b..321eaa2d 100644
--- a/library/HTMLPurifier/ConfigSchema/schema/Filter.YouTube.txt
+++ b/library/HTMLPurifier/ConfigSchema/schema/Filter.YouTube.txt
@@ -3,6 +3,11 @@ TYPE: bool
 VERSION: 3.1.0
 DEFAULT: false
 --DESCRIPTION--
+<p>
+  <strong>Warning:</strong> Deprecated in favor of %HTML.SafeObject and
+  %Output.FlashCompat (turn both on to allow YouTube videos and other
+  Flash content).
+</p>
 <p>
   This directive enables YouTube video embedding in HTML Purifier. Check
   <a href="http://htmlpurifier.org/docs/enduser-youtube.html">this document
diff --git a/library/HTMLPurifier/ConfigSchema/schema/HTML.FlashAllowFullScreen.txt b/library/HTMLPurifier/ConfigSchema/schema/HTML.FlashAllowFullScreen.txt
new file mode 100644
index 00000000..dd6d457c
--- /dev/null
+++ b/library/HTMLPurifier/ConfigSchema/schema/HTML.FlashAllowFullScreen.txt
@@ -0,0 +1,11 @@
+HTML.FlashAllowFullScreen
+TYPE: bool
+VERSION: 4.1.2
+DEFAULT: false
+--DESCRIPTION--
+<p>
+    Whether or not to permit embedded Flash content from
+    %HTML.SafeObject to expand to the full screen.  Corresponds to
+    the <code>allowFullScreen</code> parameter.
+</p>
+--# vim: et sw=4 sts=4
diff --git a/library/HTMLPurifier/Injector/SafeObject.php b/library/HTMLPurifier/Injector/SafeObject.php
index 9e178ce0..c1d8b041 100644
--- a/library/HTMLPurifier/Injector/SafeObject.php
+++ b/library/HTMLPurifier/Injector/SafeObject.php
@@ -22,6 +22,7 @@ class HTMLPurifier_Injector_SafeObject extends HTMLPurifier_Injector
         'movie' => true,
         'flashvars' => true,
         'src' => true,
+        'allowFullScreen' => true, // if omitted, assume to be 'false'
     );
 
     public function prepare($config, $context) {
diff --git a/tests/HTMLPurifier/HTMLModule/SafeObjectTest.php b/tests/HTMLPurifier/HTMLModule/SafeObjectTest.php
index 667a8a83..d8a23d50 100644
--- a/tests/HTMLPurifier/HTMLModule/SafeObjectTest.php
+++ b/tests/HTMLPurifier/HTMLModule/SafeObjectTest.php
@@ -6,8 +6,7 @@ class HTMLPurifier_HTMLModule_SafeObjectTest extends HTMLPurifier_HTMLModuleHarn
     function setUp() {
         parent::setUp();
         $this->config->set('HTML.DefinitionID', 'HTMLPurifier_HTMLModule_SafeObjectTest');
-        $def = $this->config->getHTMLDefinition(true);
-        $def->manager->addModule('SafeObject');
+        $this->config->set('HTML.SafeObject', true);
     }
 
     function testMinimal() {
@@ -38,6 +37,13 @@ class HTMLPurifier_HTMLModule_SafeObjectTest extends HTMLPurifier_HTMLModuleHarn
         );
     }
 
+    function testFullScreen() {
+        $this->config->set('HTML.FlashAllowFullScreen', true);
+        $this->assertResult(
+            '<b><object width="425" height="344" type="application/x-shockwave-flash" data="Foobar"><param name="allowScriptAccess" value="never" /><param name="allowNetworking" value="internal" /><param name="flashvars" value="foobarbaz=bally" /><param name="movie" value="http://www.youtube.com/v/RVtEQxH7PWA&amp;hl=en" /><param name="wmode" value="window" /><param name="allowFullScreen" value="true" /></object></b>'
+        );
+    }
+
 }
 
 // vim: et sw=4 sts=4