diff --git a/wp-admin/includes/template.php b/wp-admin/includes/template.php
index fc1b68873..e58e585da 100644
--- a/wp-admin/includes/template.php
+++ b/wp-admin/includes/template.php
@@ -126,33 +126,25 @@ class Walker_Category_Checklist extends Walker {
 	var $tree_type = 'category';
 	var $db_fields = array ('parent' => 'parent', 'id' => 'term_id'); //TODO: decouple this
 
-	function start_lvl($output, $depth, $args) {
+	function start_lvl(&$output, $depth, $args) {
 		$indent = str_repeat("\t", $depth);
 		$output .= "$indent<ul class='children'>\n";
-		return $output;
 	}
 
-	function end_lvl($output, $depth, $args) {
+	function end_lvl(&$output, $depth, $args) {
 		$indent = str_repeat("\t", $depth);
 		$output .= "$indent</ul>\n";
-		return $output;
 	}
 
-	function start_el($output, $category, $depth, $args) {
+	function start_el(&$output, $category, $depth, $args) {
 		extract($args);
 
 		$class = in_array( $category->term_id, $popular_cats ) ? ' class="popular-category"' : '';
 		$output .= "\n<li id='category-$category->term_id'$class>" . '<label for="in-category-' . $category->term_id . '" class="selectit"><input value="' . $category->term_id . '" type="checkbox" name="post_category[]" id="in-category-' . $category->term_id . '"' . (in_array( $category->term_id, $selected_cats ) ? ' checked="checked"' : "" ) . '/> ' . wp_specialchars( apply_filters('the_category', $category->name )) . '</label>';
-
-		return $output;
 	}
 
-	function end_el($output, $category, $depth, $args) {
-		if ( 'list' != $args['style'] )
-			return $output;
-
+	function end_el(&$output, $category, $depth, $args) {
 		$output .= "</li>\n";
-		return $output;
 	}
 }
 
diff --git a/wp-admin/post.php b/wp-admin/post.php
index 506a5635c..5ed51c86e 100644
--- a/wp-admin/post.php
+++ b/wp-admin/post.php
@@ -35,6 +35,7 @@ function redirect_post($post_ID = '') {
 		$location = $location[0] . '#postcustom';
 	} elseif (!empty($referredby) && $referredby != $referer) {
 		$location = $_POST['referredby'];
+		$location = remove_query_arg('_wp_original_http_referer', $location);
 		if ( $_POST['referredby'] == 'redo' )
 			$location = get_permalink( $post_ID );
 		elseif ( false !== strpos($location, 'edit.php') )
diff --git a/wp-includes/classes.php b/wp-includes/classes.php
index 9b127424c..0d866faac 100644
--- a/wp-includes/classes.php
+++ b/wp-includes/classes.php
@@ -395,26 +395,26 @@ class Walker {
 	var $db_fields;
 
 	//abstract callbacks
-	function start_lvl($output) { return $output; }
-	function end_lvl($output)   { return $output; }
-	function start_el($output)  { return $output; }
-	function end_el($output)    { return $output; }
+	function start_lvl(&$output) {}
+	function end_lvl(&$output)   {}
+	function start_el(&$output)  {}
+	function end_el(&$output)    {}
 
 	/*
  	 * display one element if the element doesn't have any children
  	 * otherwise, display the element and its children
  	 */
-	function display_element( $element, &$children_elements, $max_depth, $depth=0, $args, $output ) {
+	function display_element( $element, &$children_elements, $max_depth, $depth=0, $args, &$output ) {
 
-		if ( !$element)
-			return $output;
+		if ( !$element )
+			return;
 
 		$id_field = $this->db_fields['id'];
 		$parent_field = $this->db_fields['parent'];
 
 		//display this element
-		$cb_args = array_merge( array($output, $element, $depth), $args);
-		$output = call_user_func_array(array(&$this, 'start_el'), $cb_args);
+		$cb_args = array_merge( array(&$output, $element, $depth), $args);
+		call_user_func_array(array(&$this, 'start_el'), $cb_args);
 
 		if ( $max_depth == 0 ||
 		     ($max_depth != 0 &&  $max_depth > $depth+1 )) { //whether to descend
@@ -427,12 +427,12 @@ class Walker {
 					if ( !isset($newlevel) ) {
 						$newlevel = true;
 						//start the child delimiter
-						$cb_args = array_merge( array($output, $depth), $args);
-						$output = call_user_func_array(array(&$this, 'start_lvl'), $cb_args);
+						$cb_args = array_merge( array(&$output, $depth), $args);
+						call_user_func_array(array(&$this, 'start_lvl'), $cb_args);
 					}
 
 					array_splice( $children_elements, $i, 1 );
-					$output = $this->display_element( $child, $children_elements, $max_depth, $depth + 1, $args, $output );
+					$this->display_element( $child, $children_elements, $max_depth, $depth + 1, $args, $output );
 					$i = -1;
 				}
 			}
@@ -440,15 +440,13 @@ class Walker {
 
 		if ( isset($newlevel) && $newlevel ){
 			//end the child delimiter
-			$cb_args = array_merge( array($output, $depth), $args);
-			$output = call_user_func_array(array(&$this, 'end_lvl'), $cb_args);
+			$cb_args = array_merge( array(&$output, $depth), $args);
+			call_user_func_array(array(&$this, 'end_lvl'), $cb_args);
 		}
 
 		//end this element
-		$cb_args = array_merge( array($output, $element, $depth), $args);
-		$output = call_user_func_array(array(&$this, 'end_el'), $cb_args);
-
-		return $output;
+		$cb_args = array_merge( array(&$output, $element, $depth), $args);
+		call_user_func_array(array(&$this, 'end_el'), $cb_args);
 	}
 
 	/*
@@ -476,7 +474,7 @@ class Walker {
 		if ( -1 == $max_depth ) {
 			$empty_array = array();
 			foreach ( $elements as $e )
-				$output = $this->display_element( $e, $empty_array, 1, 0, $args, $output );
+				$this->display_element( $e, $empty_array, 1, 0, $args, $output );
 			return $output;
 		}
 
@@ -512,7 +510,7 @@ class Walker {
 		}
 
 		foreach ( $top_level_elements as $e )
-			$output = $this->display_element( $e, $children_elements, $max_depth, 0, $args, $output );
+			$this->display_element( $e, $children_elements, $max_depth, 0, $args, $output );
 
 		/*
 		* if we are displaying all levels, and remaining children_elements is not empty,
@@ -521,7 +519,7 @@ class Walker {
 		if ( ( $max_depth == 0 ) && sizeof( $children_elements ) > 0 ) {
 			$empty_array = array();
 			foreach ( $children_elements as $orphan_e )
-				$output = $this->display_element( $orphan_e, $empty_array, 1, 0, $args, $output );
+				$this->display_element( $orphan_e, $empty_array, 1, 0, $args, $output );
 		 }
 		 return $output;
 	}
@@ -531,19 +529,17 @@ class Walker_Page extends Walker {
 	var $tree_type = 'page';
 	var $db_fields = array ('parent' => 'post_parent', 'id' => 'ID'); //TODO: decouple this
 
-	function start_lvl($output, $depth) {
+	function start_lvl(&$output, $depth) {
 		$indent = str_repeat("\t", $depth);
 		$output .= "\n$indent<ul>\n";
-		return $output;
 	}
 
-	function end_lvl($output, $depth) {
+	function end_lvl(&$output, $depth) {
 		$indent = str_repeat("\t", $depth);
 		$output .= "$indent</ul>\n";
-		return $output;
 	}
 
-	function start_el($output, $page, $depth, $current_page, $args) {
+	function start_el(&$output, $page, $depth, $current_page, $args) {
 		if ( $depth )
 			$indent = str_repeat("\t", $depth);
 		else
@@ -571,14 +567,10 @@ class Walker_Page extends Walker {
 
 			$output .= " " . mysql2date($date_format, $time);
 		}
-
-		return $output;
 	}
 
-	function end_el($output, $page, $depth) {
+	function end_el(&$output, $page, $depth) {
 		$output .= "</li>\n";
-
-		return $output;
 	}
 
 }
@@ -587,18 +579,16 @@ class Walker_PageDropdown extends Walker {
 	var $tree_type = 'page';
 	var $db_fields = array ('parent' => 'post_parent', 'id' => 'ID'); //TODO: decouple this
 
-	function start_el($output, $page, $depth, $args) {
-				$pad = str_repeat('&nbsp;', $depth * 3);
+	function start_el(&$output, $page, $depth, $args) {
+		$pad = str_repeat('&nbsp;', $depth * 3);
 
-				$output .= "\t<option value=\"$page->ID\"";
-				if ( $page->ID == $args['selected'] )
-								$output .= ' selected="selected"';
-				$output .= '>';
-				$title = wp_specialchars($page->post_title);
-				$output .= "$pad$title";
-				$output .= "</option>\n";
-
-				return $output;
+		$output .= "\t<option value=\"$page->ID\"";
+		if ( $page->ID == $args['selected'] )
+			$output .= ' selected="selected"';
+		$output .= '>';
+		$title = wp_specialchars($page->post_title);
+		$output .= "$pad$title";
+		$output .= "</option>\n";
 	}
 }
 
@@ -606,25 +596,23 @@ class Walker_Category extends Walker {
 	var $tree_type = 'category';
 	var $db_fields = array ('parent' => 'parent', 'id' => 'term_id'); //TODO: decouple this
 
-	function start_lvl($output, $depth, $args) {
+	function start_lvl(&$output, $depth, $args) {
 		if ( 'list' != $args['style'] )
-			return $output;
+			return;
 
 		$indent = str_repeat("\t", $depth);
 		$output .= "$indent<ul class='children'>\n";
-		return $output;
 	}
 
-	function end_lvl($output, $depth, $args) {
+	function end_lvl(&$output, $depth, $args) {
 		if ( 'list' != $args['style'] )
-			return $output;
+			return;
 
 		$indent = str_repeat("\t", $depth);
 		$output .= "$indent</ul>\n";
-		return $output;
 	}
 
-	function start_el($output, $category, $depth, $args) {
+	function start_el(&$output, $category, $depth, $args) {
 		extract($args);
 
 		$cat_name = attribute_escape( $category->name);
@@ -687,16 +675,13 @@ class Walker_Category extends Walker {
 		} else {
 			$output .= "\t$link<br />\n";
 		}
-
-		return $output;
 	}
 
-	function end_el($output, $page, $depth, $args) {
+	function end_el(&$output, $page, $depth, $args) {
 		if ( 'list' != $args['style'] )
-			return $output;
+			return;
 
 		$output .= "</li>\n";
-		return $output;
 	}
 
 }
@@ -705,7 +690,7 @@ class Walker_CategoryDropdown extends Walker {
 	var $tree_type = 'category';
 	var $db_fields = array ('parent' => 'parent', 'id' => 'term_id'); //TODO: decouple this
 
-	function start_el($output, $category, $depth, $args) {
+	function start_el(&$output, $category, $depth, $args) {
 		$pad = str_repeat('&nbsp;', $depth * 3);
 
 		$cat_name = apply_filters('list_cats', $category->name, $category);
@@ -721,8 +706,6 @@ class Walker_CategoryDropdown extends Walker {
 			$output .= '&nbsp;&nbsp;' . gmdate($format, $category->last_update_timestamp);
 		}
 		$output .= "</option>\n";
-
-		return $output;
 	}
 }