--- a/accessible/base/AccEvent.h
+++ b/accessible/base/AccEvent.h
@@ -46,20 +46,16 @@ public:
     //    This event will always be emitted. This flag is used for events that
     //    don't support coalescence.
     eAllowDupes,
 
      // eCoalesceReorder : For reorder events from the same subtree or the same
      //    node, only the umbrella event on the ancestor will be emitted.
     eCoalesceReorder,
 
-     // eCoalesceMutationTextChange : coalesce text change events caused by
-     // tree mutations of the same tree level.
-    eCoalesceMutationTextChange,
-
     // eCoalesceOfSameType : For events of the same type, only the newest event
     // will be processed.
     eCoalesceOfSameType,
 
     // eCoalesceSelectionChange: coalescence of selection change events.
     eCoalesceSelectionChange,
 
     // eCoalesceStateChange: coalesce state change events.
@@ -209,17 +205,17 @@ private:
 
 /**
  * Base class for show and hide accessible events.
  */
 class AccMutationEvent: public AccEvent
 {
 public:
   AccMutationEvent(uint32_t aEventType, Accessible* aTarget) :
-    AccEvent(aEventType, aTarget, eAutoDetect, eCoalesceMutationTextChange)
+    AccEvent(aEventType, aTarget, eAutoDetect, eCoalesceReorder)
   {
     // Don't coalesce these since they are coalesced by reorder event. Coalesce
     // contained text change events.
     mParent = mAccessible->Parent();
   }
   virtual ~AccMutationEvent() { }
 
   // Event

--- a/accessible/base/EventQueue.cpp
+++ b/accessible/base/EventQueue.cpp
@@ -85,21 +85,25 @@ void
 EventQueue::CoalesceEvents()
 {
   NS_ASSERTION(mEvents.Length(), "There should be at least one pending event!");
   uint32_t tail = mEvents.Length() - 1;
   AccEvent* tailEvent = mEvents[tail];
 
   switch(tailEvent->mEventRule) {
     case AccEvent::eCoalesceReorder:
-      MOZ_ASSERT(tailEvent->mAccessible->IsApplication() ||
-                 tailEvent->mAccessible->IsOuterDoc() ||
-                 tailEvent->mAccessible->IsXULTree(),
+    {
+      DebugOnly<Accessible*> target = tailEvent->mAccessible.get();
+      MOZ_ASSERT(target->IsApplication() ||
+                 target->IsOuterDoc() ||
+                 target->IsXULTree(),
                  "Only app or outerdoc accessible reorder events are in the queue");
+      MOZ_ASSERT(tailEvent->GetEventType() == nsIAccessibleEvent::EVENT_REORDER, "only reorder events should be queued");
       break; // case eCoalesceReorder
+    }
 
     case AccEvent::eCoalesceOfSameType:
     {
       // Coalesce old events by newer event.
       for (uint32_t index = tail - 1; index < tail; index--) {
         AccEvent* accEvent = mEvents[index];
         if (accEvent->mEventType == tailEvent->mEventType &&
           accEvent->mEventRule == tailEvent->mEventRule) {