--- a/accessible/jsat/AccessFu.jsm
+++ b/accessible/jsat/AccessFu.jsm
@@ -301,19 +301,21 @@ this.AccessFu = { // jshint ignore:line
   onEvent: function(event, data, callback) {
     switch (event) {
       case "Accessibility:Settings":
         this._systemPref = data.enabled;
         this._enableOrDisable();
         break;
       case "Accessibility:NextObject":
       case "Accessibility:PreviousObject": {
-        let rule = data ?
-          data.rule.substr(0, 1).toUpperCase() + data.rule.substr(1).toLowerCase() :
-          "Simple";
+        let rule = "Simple";
+        if (data && data.rule && data.rule.length) {
+          rule = data.rule.substr(0, 1).toUpperCase() +
+            data.rule.substr(1).toLowerCase();
+        }
         let method = event.replace(/Accessibility:(\w+)Object/, "move$1");
         this.Input.moveCursor(method, rule, "gesture");
         break;
       }
       case "Accessibility:ActivateObject":
         this.Input.activateCurrent(data);
         break;
       case "Accessibility:LongPress":