Index: wp-includes/user.php
===================================================================
--- wp-includes/user.php	(revision 17188)
+++ wp-includes/user.php	(working copy)
@@ -422,7 +422,7 @@
 		}
 
 		$this->query_from = "FROM $wpdb->users";
-		$this->query_where = "WHERE 1=1";
+		$this->query_where = "1=1"; // Prepend WHERE later
 
 		// sorting
 		if ( in_array( $qv['orderby'], array('nicename', 'email', 'url', 'registered') ) ) {
@@ -515,12 +515,14 @@
 
 		if ( !empty( $qv['include'] ) ) {
 			$ids = implode( ',', wp_parse_id_list( $qv['include'] ) );
-			$this->query_where .= " AND $wpdb->users.ID IN ($ids)";
+			$this->query_where = ' ( ' . $this->query_where . " ) OR $wpdb->users.ID IN ($ids)";
 		} elseif ( !empty($qv['exclude']) ) {
 			$ids = implode( ',', wp_parse_id_list( $qv['exclude'] ) );
 			$this->query_where .= " AND $wpdb->users.ID NOT IN ($ids)";
 		}
 
+		$this->query_where = 'WHERE ' . $this->query_where;
+
 		do_action_ref_array( 'pre_user_query', array( &$this ) );
 	}
 
Index: wp-admin/includes/meta-boxes.php
===================================================================
--- wp-admin/includes/meta-boxes.php	(revision 17188)
+++ wp-admin/includes/meta-boxes.php	(working copy)
@@ -527,10 +527,12 @@
 ?>
 <label class="screen-reader-text" for="post_author_override"><?php _e('Author'); ?></label>
 <?php
+	$current_author = empty($post->ID) ? $user_ID : $post->post_author;
 	wp_dropdown_users( array(
 		'who' => 'authors',
 		'name' => 'post_author_override',
-		'selected' => empty($post->ID) ? $user_ID : $post->post_author
+		'selected' => $current_author,
+		'include' => $current_author
 	) );
 }