--- tests/Zend/View/Helper/FormRadioTest.php	(revision 12418)
+++ tests/Zend/View/Helper/FormRadioTest.php	(working copy)
@@ -340,6 +340,19 @@
             $this->assertRegexp('/<input([^>]*)(id="' . $id . '")/', $html);
         }
     }
+    
+    public function testDashesShouldNotBeFilteredFromId()
+    {
+        $name = "Foo";
+        $value = -1;
+        $options = array($value => "Bar");
+        $formRadio = new Zend_View_Helper_FormRadio();
+        $formRadio->setView(new Zend_View());
+        $html = $formRadio->formRadio($name, $value, null, $options);
+        $correct = 'id="' . $name . '-' . strval($value) . '"';
+        $position = strpos($html, $correct);
+        $this->assertType("numeric", $position);
+    }
 }
 
 // Call Zend_View_Helper_FormRadioTest::main() if this source file is executed directly.
Index: library/Zend/View/Helper/FormRadio.php
===================================================================
--- library/Zend/View/Helper/FormRadio.php	(revision 12418)
+++ library/Zend/View/Helper/FormRadio.php	(working copy)
@@ -128,9 +128,17 @@
             $endTag= '>';
         }
 
+        // filter is same as Alnum, except - and _ are allowed also (ZF-4191)
+        require_once 'Zend/Filter/PregReplace.php';
+        $unicodeEnabled = (@preg_match('/\pL/u', 'a')) ? true : false;
+        if (! $unicodeEnabled) {
+            $pattern = '/[^a-zA-Z0-9\-\_]/';
+        } else {
+            $pattern = '/[^\p{L}\p{N}\-\_]/u';
+        }
+        $filter = new Zend_Filter_PregReplace($pattern, "");
+        
         // add radio buttons to the list.
-        require_once 'Zend/Filter/Alnum.php';
-        $filter = new Zend_Filter_Alnum();
         foreach ($options as $opt_value => $opt_label) {
 
             // Should the label be escaped?