diff --git a/accessible/base/nsCoreUtils.cpp b/accessible/base/nsCoreUtils.cpp
index 192d1b3be830..27e34e76f377 100644
--- a/accessible/base/nsCoreUtils.cpp
+++ b/accessible/base/nsCoreUtils.cpp
@@ -10,7 +10,6 @@
 #include "nsIBaseWindow.h"
 #include "nsIDocShellTreeOwner.h"
 #include "nsIDocument.h"
-#include "nsIDOMHTMLElement.h"
 #include "nsRange.h"
 #include "nsIBoxObject.h"
 #include "nsXULElement.h"
diff --git a/accessible/generic/Accessible.cpp b/accessible/generic/Accessible.cpp
index 2a021343000b..36592f000226 100644
--- a/accessible/generic/Accessible.cpp
+++ b/accessible/generic/Accessible.cpp
@@ -31,7 +31,6 @@
 
 #include "nsIDOMElement.h"
 #include "nsIDOMNodeFilter.h"
-#include "nsIDOMHTMLElement.h"
 #include "nsIDOMKeyEvent.h"
 #include "nsIDOMTreeWalker.h"
 #include "nsIDOMXULButtonElement.h"
diff --git a/accessible/tests/mochitest/common.js b/accessible/tests/mochitest/common.js
index ee61b1ab5a86..7465db13ed2f 100644
--- a/accessible/tests/mochitest/common.js
+++ b/accessible/tests/mochitest/common.js
@@ -47,7 +47,6 @@ const nsIObserverService = Components.interfaces.nsIObserverService;
 const nsIDOMDocument = Components.interfaces.nsIDOMDocument;
 const nsIDOMEvent = Components.interfaces.nsIDOMEvent;
 const nsIDOMNode = Components.interfaces.nsIDOMNode;
-const nsIDOMHTMLElement = Components.interfaces.nsIDOMHTMLElement;
 const nsIDOMWindow = Components.interfaces.nsIDOMWindow;
 const nsIDOMXULElement = Components.interfaces.nsIDOMXULElement;
 
diff --git a/accessible/tests/mochitest/events.js b/accessible/tests/mochitest/events.js
index fead811f9f58..c988338d8677 100644
--- a/accessible/tests/mochitest/events.js
+++ b/accessible/tests/mochitest/events.js
@@ -1059,19 +1059,11 @@ function synthClick(aNodeOrID, aCheckerOrEventSeq, aArgs) {
     }
 
     // Scroll the node into view, otherwise synth click may fail.
-    if (targetNode instanceof nsIDOMHTMLElement) {
-      targetNode.scrollIntoView(true);
-    } else if (targetNode instanceof nsIDOMXULElement) {
-      var targetAcc = getAccessible(targetNode);
-      targetAcc.scrollTo(SCROLL_TYPE_ANYWHERE);
-    }
+    targetNode.scrollIntoView(true);
 
     var x = 1, y = 1;
     if (aArgs && ("where" in aArgs) && aArgs.where == "right") {
-      if (targetNode instanceof nsIDOMHTMLElement)
-        x = targetNode.offsetWidth - 1;
-      else if (targetNode instanceof nsIDOMXULElement)
-        x = targetNode.boxObject.width - 1;
+      x = targetNode.getBoundingClientRect().width - 1;
     }
     synthesizeMouse(targetNode, x, y, aArgs ? aArgs : {});
   };
diff --git a/accessible/windows/sdn/sdnAccessible.cpp b/accessible/windows/sdn/sdnAccessible.cpp
index 4a92c1c1a9ba..b248edbbfab4 100644
--- a/accessible/windows/sdn/sdnAccessible.cpp
+++ b/accessible/windows/sdn/sdnAccessible.cpp
@@ -12,7 +12,6 @@
 #include "nsAttrName.h"
 #include "nsCoreUtils.h"
 #include "nsIAccessibleTypes.h"
-#include "nsIDOMHTMLElement.h"
 #include "nsICSSDeclaration.h"
 #include "nsNameSpaceManager.h"
 #include "nsServiceManagerUtils.h"