Index: wp-includes/default-widgets.php
===================================================================
--- wp-includes/default-widgets.php	(revision 23314)
+++ wp-includes/default-widgets.php	(working copy)
@@ -558,9 +558,8 @@
 		ob_start();
 		extract($args);
 
-		$title = apply_filters('widget_title', empty($instance['title']) ? __('Recent Posts') : $instance['title'], $instance, $this->id_base);
-		if ( empty( $instance['number'] ) || ! $number = absint( $instance['number'] ) )
- 			$number = 10;
+		$title     = apply_filters( 'widget_title', empty( $instance['title'] ) ? __( 'Recent Posts' ) : $instance['title'], $instance, $this->id_base );
+		$number    = ! empty( $instance['number'] ) ? absint( $instance['number'] ) : 10;
 		$show_date = isset( $instance['show_date'] ) ? $instance['show_date'] : false;
 
 		$r = new WP_Query( apply_filters( 'widget_posts_args', array( 'posts_per_page' => $number, 'no_found_rows' => true, 'post_status' => 'publish', 'ignore_sticky_posts' => true ) ) );
@@ -609,7 +608,7 @@
 
 	function form( $instance ) {
 		$title     = isset( $instance['title'] ) ? esc_attr( $instance['title'] ) : '';
-		$number    = isset( $instance['number'] ) ? absint( $instance['number'] ) : 5;
+		$number    = ! empty( $instance['number'] ) ? absint( $instance['number'] ) : 5;
 		$show_date = isset( $instance['show_date'] ) ? (bool) $instance['show_date'] : false;
 ?>
 		<p><label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label>
@@ -674,11 +673,9 @@
 
  		extract($args, EXTR_SKIP);
  		$output = '';
-		$title = apply_filters( 'widget_title', empty( $instance['title'] ) ? __( 'Recent Comments' ) : $instance['title'], $instance, $this->id_base );
+		$title  = apply_filters( 'widget_title', empty( $instance['title'] ) ? __( 'Recent Comments' ) : $instance['title'], $instance, $this->id_base );
+		$number = ! empty( $instance['number'] ) ? absint( $instance['number'] ) : 5;
 
-		if ( empty( $instance['number'] ) || ! $number = absint( $instance['number'] ) )
- 			$number = 5;
-
 		$comments = get_comments( apply_filters( 'widget_comments_args', array( 'number' => $number, 'status' => 'approve', 'post_status' => 'publish' ) ) );
 		$output .= $before_widget;
 		if ( $title )
@@ -716,8 +713,8 @@
 	}
 
 	function form( $instance ) {
-		$title = isset($instance['title']) ? esc_attr($instance['title']) : '';
-		$number = isset($instance['number']) ? absint($instance['number']) : 5;
+		$title = isset( $instance['title'] ) ? esc_attr( $instance['title'] ) : '';
+		$number = ! empty( $instance['number'] ) ? absint( $instance['number'] ) : 5;
 ?>
 		<p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title:'); ?></label>
 		<input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo $title; ?>" /></p>