diff --git a/dom/xul/XULDocument.cpp b/dom/xul/XULDocument.cpp
index 283dcce8d776..b4534b13e7ea 100644
--- a/dom/xul/XULDocument.cpp
+++ b/dom/xul/XULDocument.cpp
@@ -3603,8 +3603,7 @@ XULDocument::OverlayForwardReference::Merge(Element* aTargetElement,
         if (attr == nsGkAtoms::removeelement && value.EqualsLiteral("true")) {
             nsCOMPtr<nsINode> parent = aTargetElement->GetParentNode();
             if (!parent) return NS_ERROR_FAILURE;
-            rv = RemoveElement(parent, aTargetElement);
-            if (NS_FAILED(rv)) return rv;
+            parent->RemoveChildNode(aTargetElement, true);
             return NS_OK;
         }
 
@@ -3671,13 +3670,19 @@ XULDocument::OverlayForwardReference::Merge(Element* aTargetElement,
                 // non-null ID.
                 rv = Merge(elementInDocument, currContent->AsElement(), aNotify);
                 if (NS_FAILED(rv)) return rv;
-                aOverlayElement->RemoveChildAt_Deprecated(0, false);
+                nsIContent* firstChild = aOverlayElement->GetFirstChild();
+                if (firstChild) {
+                  aOverlayElement->RemoveChildNode(firstChild, false);
+                }
 
                 continue;
             }
         }
 
-        aOverlayElement->RemoveChildAt_Deprecated(0, false);
+        nsIContent* firstChild = aOverlayElement->GetFirstChild();
+        if (firstChild) {
+          aOverlayElement->RemoveChildNode(firstChild, false);
+        }
 
         rv = InsertElement(aTargetElement, currContent, aNotify);
         if (NS_FAILED(rv)) return rv;
@@ -4037,15 +4042,6 @@ XULDocument::InsertElement(nsINode* aParent, nsIContent* aChild, bool aNotify)
     return NS_OK;
 }
 
-nsresult
-XULDocument::RemoveElement(nsINode* aParent, nsINode* aChild)
-{
-    int32_t nodeOffset = aParent->ComputeIndexOf(aChild);
-
-    aParent->RemoveChildAt_Deprecated(nodeOffset, true);
-    return NS_OK;
-}
-
 //----------------------------------------------------------------------
 //
 // CachedChromeStreamListener
diff --git a/dom/xul/XULDocument.h b/dom/xul/XULDocument.h
index 49384924aa12..1c57012e41c6 100644
--- a/dom/xul/XULDocument.h
+++ b/dom/xul/XULDocument.h
@@ -524,10 +524,6 @@ protected:
     nsresult
     InsertElement(nsINode* aParent, nsIContent* aChild, bool aNotify);
 
-    static
-    nsresult
-    RemoveElement(nsINode* aParent, nsINode* aChild);
-
     /**
      * The current prototype that we are walking to construct the
      * content model.