Index: wp-admin/includes/template.php
===================================================================
--- wp-admin/includes/template.php	(revision 19940)
+++ wp-admin/includes/template.php	(working copy)
@@ -121,7 +121,7 @@
 		$categories = (array) get_terms($taxonomy, array('get' => 'all'));
 	}
 
-	if ( $checked_ontop ) {
+	if ( apply_filters( 'show_checked_terms_on_top', $checked_ontop, $taxonomy ) ) {
 		// Post process $categories rather than adding an exclude to the get_terms() query to keep the query the same across all posts (for any query cache)
 		$checked_categories = array();
 		$keys = array_keys( $categories );