Index: src/wp-admin/includes/ajax-actions.php
===================================================================
--- src/wp-admin/includes/ajax-actions.php	(revision 28260)
+++ src/wp-admin/includes/ajax-actions.php	(working copy)
@@ -638,7 +638,6 @@
 	global $wp_list_table;
 
 	check_ajax_referer( 'add-tag', '_wpnonce_add-tag' );
-	$post_type = !empty($_POST['post_type']) ? $_POST['post_type'] : 'post';
 	$taxonomy = !empty($_POST['taxonomy']) ? $_POST['taxonomy'] : 'post_tag';
 	$tax = get_taxonomy($taxonomy);
 
@@ -878,8 +877,6 @@
 	edit_comment();
 
 	$position = ( isset($_POST['position']) && (int) $_POST['position']) ? (int) $_POST['position'] : '-1';
-	$comments_status = isset($_POST['comments_listing']) ? $_POST['comments_listing'] : '';
-
 	$checkbox = ( isset($_POST['checkbox']) && true == $_POST['checkbox'] ) ? 1 : 0;
 	$wp_list_table = _get_list_table( $checkbox ? 'WP_Comments_List_Table' : 'WP_Post_Comments_List_Table', array( 'screen' => 'edit-comments' ) );
 
@@ -1122,8 +1119,7 @@
 
 function wp_ajax_hidden_columns() {
 	check_ajax_referer( 'screen-options-nonce', 'screenoptionnonce' );
-	$hidden = isset( $_POST['hidden'] ) ? $_POST['hidden'] : '';
-	$hidden = explode( ',', $_POST['hidden'] );
+	$hidden = explode( ',', isset( $_POST['hidden'] ) ? $_POST['hidden'] : '' );
 	$page = isset( $_POST['page'] ) ? $_POST['page'] : '';
 
 	if ( $page != sanitize_key( $page ) )
@@ -1332,8 +1328,6 @@
 
 	$wp_list_table = _get_list_table( 'WP_Posts_List_Table', array( 'screen' => $_POST['screen'] ) );
 
-	$mode = $_POST['post_view'];
-
 	$level = 0;
 	$request_post = array( get_post( $_POST['post_ID'] ) );
 	$parent = $request_post[0]->post_parent;
@@ -1403,7 +1397,6 @@
 	unset( $post_types['attachment'] );
 
 	$s = wp_unslash( $_POST['ps'] );
-	$searchand = $search = '';
 	$args = array(
 		'post_type' => array_keys( $post_types ),
 		'post_status' => 'any',
@@ -1709,16 +1702,11 @@
 function wp_ajax_wp_fullscreen_save_post() {
 	$post_id = isset( $_POST['post_ID'] ) ? (int) $_POST['post_ID'] : 0;
 
-	$post = $post_type = null;
+	$post = null;
 
 	if ( $post_id )
 		$post = get_post( $post_id );
 
-	if ( $post )
-		$post_type = $post->post_type;
-	elseif ( isset( $_POST['post_type'] ) && post_type_exists( $_POST['post_type'] ) )
-		$post_type = $_POST['post_type'];
-
 	check_ajax_referer('update-post_' . $post_id, '_wpnonce');
 
 	$post_id = edit_post();
@@ -1967,8 +1955,6 @@
 	if ( ! current_user_can( 'edit_post', $post_id ) )
 		wp_send_json_error();
 
-	$post = get_post( $post_id, ARRAY_A );
-
 	foreach ( $attachments as $attachment_id => $menu_order ) {
 		if ( ! current_user_can( 'edit_post', $attachment_id ) )
 			continue;
@@ -2011,7 +1997,7 @@
 	}
 
 	$rel = $url = '';
-	$html = $title = isset( $attachment['post_title'] ) ? $attachment['post_title'] : '';
+	$html = isset( $attachment['post_title'] ) ? $attachment['post_title'] : '';
 	if ( ! empty( $attachment['url'] ) ) {
 		$url = $attachment['url'];
 		if ( strpos( $url, 'attachment_id') || get_attachment_link( $id ) == $url )