Index: wp-includes/default-widgets.php
===================================================================
--- wp-includes/default-widgets.php	(revision 18636)
+++ wp-includes/default-widgets.php	(working copy)
@@ -177,7 +177,7 @@
 
 	function widget( $args, $instance ) {
 		extract($args);
-		$title = apply_filters('widget_title', $instance['title'], $instance, $this->id_base);
+		$title = apply_filters( 'widget_title', empty( $instance['title'] ) ? '' : $instance['title'], $instance, $this->id_base );
 
 		echo $before_widget;
 		if ( $title )
@@ -379,7 +379,7 @@
 		$text = apply_filters( 'widget_text', $instance['text'], $instance );
 		echo $before_widget;
 		if ( !empty( $title ) ) { echo $before_title . $title . $after_title; } ?>
-			<div class="textwidget"><?php echo $instance['filter'] ? wpautop($text) : $text; ?></div>
+			<div class="textwidget"><?php echo !empty( $instance['filter'] ) ? wpautop($text) : $text; ?></div>
 		<?php
 		echo $after_widget;
 	}
@@ -1064,7 +1064,7 @@
 		if ( !$nav_menu )
 			return;
 
-		$instance['title'] = apply_filters('widget_title', $instance['title'], $instance, $this->id_base);
+		$instance['title'] = apply_filters( 'widget_title', empty( $instance['title'] ) ? '' : $instance['title'], $instance, $this->id_base );
 
 		echo $args['before_widget'];