Index: wp-includes/query.php
===================================================================
--- wp-includes/query.php	(revision 21780)
+++ wp-includes/query.php	(working copy)
@@ -1787,13 +1787,13 @@
 		// Tag stuff
 		if ( '' != $q['tag'] && !$this->is_singular && $this->query_vars_changed ) {
 			if ( strpos($q['tag'], ',') !== false ) {
-				$tags = preg_split('/[,\s]+/', $q['tag']);
+				$tags = preg_split('/[,\r\n\t ]+/', $q['tag']);
 				foreach ( (array) $tags as $tag ) {
 					$tag = sanitize_term_field('slug', $tag, 0, 'post_tag', 'db');
 					$q['tag_slug__in'][] = $tag;
 				}
-			} else if ( preg_match('/[+\s]+/', $q['tag']) || !empty($q['cat']) ) {
-				$tags = preg_split('/[+\s]+/', $q['tag']);
+			} else if ( preg_match('/[+\r\n\t ]+/', $q['tag']) || !empty($q['cat']) ) {
+				$tags = preg_split('/[+\r\n\t ]+/', $q['tag']);
 				foreach ( (array) $tags as $tag ) {
 					$tag = sanitize_term_field('slug', $tag, 0, 'post_tag', 'db');
 					$q['tag_slug__and'][] = $tag;