Don't process keypress if the current row is null. see #7643

git-svn-id: https://develop.svn.wordpress.org/trunk@8779 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/js/jquery/jquery.table-hotkeys.js

@@ -37,6 +37,7 @@
 		}
 		var make_key_callback = function(expr) {
 			return function() {
+				if ( null == $.table_hotkeys.current_row ) return false;
 				var clickable = $(expr, $.table_hotkeys.current_row).filter(':visible');
 				if (!$($(clickable[0]).parent()[0]).is(':visible')) return false;
 				if (clickable.is('.'+destructive_class)) next_row() || prev_row();