diff --git a/mozilla/accessible/src/base/nsAccessible.cpp b/mozilla/accessible/src/base/nsAccessible.cpp
index 88d5bb8f978..39e604cdf99 100644
--- a/mozilla/accessible/src/base/nsAccessible.cpp
+++ b/mozilla/accessible/src/base/nsAccessible.cpp
@@ -829,7 +829,7 @@ NS_IMETHODIMP nsAccessible::TestChildCache(nsIAccessible *aCachedChild)
   // It will assert if not all the children were created
   // when they were first cached, and no invalidation
   // ever corrected parent accessible's child cache.
-  if (mAccChildCount == eChildCountUninitialized) {
+  if (mAccChildCount <= 0) {
     return NS_OK;
   }
   nsCOMPtr<nsIAccessible> sibling = mFirstChild;
diff --git a/mozilla/accessible/src/base/nsOuterDocAccessible.cpp b/mozilla/accessible/src/base/nsOuterDocAccessible.cpp
index f703cee6301..a0c087bb436 100644
--- a/mozilla/accessible/src/base/nsOuterDocAccessible.cpp
+++ b/mozilla/accessible/src/base/nsOuterDocAccessible.cpp
@@ -116,7 +116,7 @@ void nsOuterDocAccessible::CacheChildren()
     return;
   }
 
-  SetFirstChild(nsnull);
+  InvalidateChildren();
   mAccChildCount = 0;
 
   // In these variable names, "outer" relates to the nsOuterDocAccessible