diff --git a/accessible/tests/mochitest/events.js b/accessible/tests/mochitest/events.js
index f7b6f40bc17..027a32b8b8d 100644
--- a/accessible/tests/mochitest/events.js
+++ b/accessible/tests/mochitest/events.js
@@ -345,10 +345,17 @@ function eventQueue(aEventType)
                 var msg = "Test with ID = '" + this.getEventID(checker) +
                   "' succeed. ";
 
-                if (checker.unexpected)
-                  ok(true, msg + "There's no unexpected " + typeStr + " event.");
-                else
+                if (checker.unexpected) {
+                  if (checker.todo) {
+                    todo(false, "Event " + typeStr + " event is still missing");
+                  }
+                  else {
+                    ok(true, msg + "There's no unexpected " + typeStr + " event.");
+                  }
+                }
+                else {
                   ok(true, msg + "Event " + typeStr + " was handled.");
+                }
               }
             }
           }
@@ -371,8 +378,13 @@ function eventQueue(aEventType)
                 ok(false, msg + "Dupe " + typeStr + " event.");
 
               if (checker.unexpected) {
-                if (checker.wasCaught)
+                if (checker.todo) {
+                  todo(checker.wasCaught,
+                       "Event " + typeStr + " event is still missing");
+                }
+                else if (checker.wasCaught) {
                   ok(false, msg + "There's unexpected " + typeStr + " event.");
+                }
               } else if (!checker.wasCaught) {
                 ok(false, msg + typeStr + " event was missed.");
               }
@@ -1667,6 +1679,18 @@ function invokerChecker(aEventType, aTargetOrFunc, aTargetFuncArg, aIsAsync)
   this.mTargetFuncArg = aTargetFuncArg;
 }
 
+/**
+ * Generic invoker checker for todo events.
+ */
+function todo_invokerChecker(aEventType, aTargetOrFunc, aTargetFuncArg)
+{
+  this.__proto__ = new invokerChecker(aEventType, aTargetOrFunc,
+                                      aTargetFuncArg, true);
+
+  this.unexpected = true;
+  this.todo = true;
+}
+
 /**
  * Generic invoker checker for unexpected events.
  */
diff --git a/accessible/tests/mochitest/events/test_mutation.html b/accessible/tests/mochitest/events/test_mutation.html
index 8eadd521ccb..92a5f35fe24 100644
--- a/accessible/tests/mochitest/events/test_mutation.html
+++ b/accessible/tests/mochitest/events/test_mutation.html
@@ -358,6 +358,25 @@
       }
     }
 
+    function showHiddenParentOfVisibleChild()
+    {
+      this.eventSeq = [
+        new todo_invokerChecker(EVENT_HIDE, getNode("c4_child")),
+        new invokerChecker(EVENT_SHOW, getNode("c4_middle")),
+        new invokerChecker(EVENT_REORDER, getNode("c4"))
+      ];
+
+      this.invoke = function showHiddenParentOfVisibleChild_invoke()
+      {
+        getNode("c4_middle").style.visibility = 'visible';
+      }
+
+      this.getID = function showHiddenParentOfVisibleChild_getID()
+      {
+        return "show hidden parent of visible child";
+      }
+    }
+
     /**
      * Target getters.
      */
@@ -484,6 +503,7 @@
       gQueue.push(new test2("testContainer", "testNestedContainer"));
       gQueue.push(new test3("testContainer"));
       gQueue.push(new insertReferredElm("testContainer3"));
+      gQueue.push(new showHiddenParentOfVisibleChild());
 
       gQueue.invoke(); // Will call SimpleTest.finish();
     }
@@ -544,5 +564,11 @@
   </div>
   <div id="testContainer2"></div>
   <div id="testContainer3"></div>
+
+  <div id="c4">
+    <div style="visibility:hidden" id="c4_middle">
+     <div style="visibility:visible" id="c4_child"></div>
+   </div>
+  </div>
 </body>
 </html>