Index: wp-admin/includes/class-wp-ms-themes-list-table.php
===================================================================
--- wp-admin/includes/class-wp-ms-themes-list-table.php	(revision 16557)
+++ wp-admin/includes/class-wp-ms-themes-list-table.php	(working copy)
@@ -25,12 +25,10 @@
 
 		$page = $this->get_pagenum();
 
-		if ( !isset($this->is_site_themes) ) {
-			$screen = get_current_screen();
-			$this->is_site_themes = ( 'site-themes-network' == $screen->id ) ? true : false;
-		}
+		$screen = get_current_screen();
+		$this->is_site_themes = ( 'site-themes-network' == $screen->id ) ? true : false;
 
-		if ( $this->is_site_themes && ! isset( $this->site_id ) )
+		if ( $this->is_site_themes )
 			$this->site_id = isset( $_REQUEST['id'] ) ? intval( $_REQUEST['id'] ) : 0;
 
 		parent::WP_List_Table( array(
Index: wp-admin/network/site-themes.php
===================================================================
--- wp-admin/network/site-themes.php	(revision 16557)
+++ wp-admin/network/site-themes.php	(working copy)
@@ -28,8 +28,6 @@
 if ( ! $id )
 	wp_die( __('Invalid site ID.') );
 
-$wp_list_table->site_id = $id;
-$wp_list_table->is_site_themes = true;
 $wp_list_table->prepare_items();
 
 $details = get_blog_details( $id );