Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 28047)
+++ wp-includes/functions.php	(working copy)
@@ -2847,8 +2847,17 @@
 
 		$matched = 0;
 		foreach ( $args as $m_key => $m_value ) {
-			if ( array_key_exists( $m_key, $to_match ) && $m_value == $to_match[ $m_key ] )
-				$matched++;
+			if ( array_key_exists( $m_key, $to_match ) ) {
+        if ( $m_value == $to_match[ $m_key ] ) {
+				  $matched++;
+        } elseif ( is_array( $m_value ) && is_array( $to_match[ $m_key ] ) ) {
+          foreach ( $m_value as $mv_key => $mv_value ) {
+            if ( in_array( $mv_value, $to_match[ $m_key ] ) ) {
+              $matched = $count;
+            }
+          }  
+        } 
+      }
 		}
 
 		if ( ( 'AND' == $operator && $matched == $count )