Fix #3131
diff --git a/system/helpers/url_helper.php b/system/helpers/url_helper.php
index dff1a86..4493d5b 100644
--- a/system/helpers/url_helper.php
+++ b/system/helpers/url_helper.php
@@ -208,6 +208,10 @@
 			$window_name = $attributes['window_name'];
 			unset($attributes['window_name']);
 		}
+		else
+		{
+			$window_name = '_blank';
+		}
 
 		foreach (array('width' => '800', 'height' => '600', 'scrollbars' => 'yes', 'status' => 'yes', 'resizable' => 'yes', 'screenx' => '0', 'screeny' => '0') as $key => $val)
 		{