diff --git a/accessible/ipc/DocAccessibleChild.cpp b/accessible/ipc/DocAccessibleChild.cpp
index 61c76d8555cc..a88edd32ea33 100644
--- a/accessible/ipc/DocAccessibleChild.cpp
+++ b/accessible/ipc/DocAccessibleChild.cpp
@@ -294,13 +294,14 @@ bool
 DocAccessibleChild::RecvTextSubstring(const uint64_t& aID,
                                       const int32_t& aStartOffset,
                                       const int32_t& aEndOffset,
-                                      nsString* aText)
+                                      nsString* aText, bool* aValid)
 {
   HyperTextAccessible* acc = IdToHyperTextAccessible(aID);
   if (!acc) {
     return true;
   }
 
+  *aValid = acc->IsValidRange(aStartOffset, aEndOffset);
   acc->TextSubstring(aStartOffset, aEndOffset, *aText);
   return true;
 }
@@ -561,10 +562,11 @@ DocAccessibleChild::RecvReplaceText(const uint64_t& aID,
 bool
 DocAccessibleChild::RecvInsertText(const uint64_t& aID,
                                    const nsString& aText,
-                                   const int32_t& aPosition)
+                                   const int32_t& aPosition, bool* aValid)
 {
   HyperTextAccessible* acc = IdToHyperTextAccessible(aID);
   if (acc && acc->IsTextRole()) {
+    *aValid = acc->IsValidOffset(aPosition);
     acc->InsertText(aText, aPosition);
   }
 
@@ -574,7 +576,7 @@ DocAccessibleChild::RecvInsertText(const uint64_t& aID,
 bool
 DocAccessibleChild::RecvCopyText(const uint64_t& aID,
                                  const int32_t& aStartPos,
-                                 const int32_t& aEndPos)
+                                 const int32_t& aEndPos, bool* aValid)
 {
   HyperTextAccessible* acc = IdToHyperTextAccessible(aID);
   if (acc && acc->IsTextRole()) {
@@ -587,10 +589,11 @@ DocAccessibleChild::RecvCopyText(const uint64_t& aID,
 bool
 DocAccessibleChild::RecvCutText(const uint64_t& aID,
                                 const int32_t& aStartPos,
-                                const int32_t& aEndPos)
+                                const int32_t& aEndPos, bool* aValid)
 {
   HyperTextAccessible* acc = IdToHyperTextAccessible(aID);
   if (acc && acc->IsTextRole()) {
+    *aValid = acc->IsValidRange(aStartPos, aEndPos);
     acc->CutText(aStartPos, aEndPos);
   }
 
@@ -600,10 +603,11 @@ DocAccessibleChild::RecvCutText(const uint64_t& aID,
 bool
 DocAccessibleChild::RecvDeleteText(const uint64_t& aID,
                                    const int32_t& aStartPos,
-                                   const int32_t& aEndPos)
+                                   const int32_t& aEndPos, bool* aValid)
 {
   HyperTextAccessible* acc = IdToHyperTextAccessible(aID);
   if (acc && acc->IsTextRole()) {
+    *aValid = acc->IsValidRange(aStartPos, aEndPos);
     acc->DeleteText(aStartPos, aEndPos);
   }
 
@@ -612,10 +616,11 @@ DocAccessibleChild::RecvDeleteText(const uint64_t& aID,
 
 bool
 DocAccessibleChild::RecvPasteText(const uint64_t& aID,
-                                  const int32_t& aPosition)
+                                  const int32_t& aPosition, bool* aValid)
 {
   HyperTextAccessible* acc = IdToHyperTextAccessible(aID);
   if (acc && acc->IsTextRole()) {
+    *aValid = acc->IsValidOffset(aPosition);
     acc->PasteText(aPosition);
   }
 
diff --git a/accessible/ipc/DocAccessibleChild.h b/accessible/ipc/DocAccessibleChild.h
index 8e8a63537bed..ebd07f44f4c8 100644
--- a/accessible/ipc/DocAccessibleChild.h
+++ b/accessible/ipc/DocAccessibleChild.h
@@ -75,8 +75,8 @@ public:
 
   virtual bool RecvTextSubstring(const uint64_t& aID,
                                  const int32_t& aStartOffset,
-                                 const int32_t& aEndOffset, nsString* aText)
-    override;
+                                 const int32_t& aEndOffset, nsString* aText,
+                                 bool* aValid) override;
 
   virtual bool RecvGetTextAfterOffset(const uint64_t& aID,
                                       const int32_t& aOffset,
@@ -166,22 +166,22 @@ public:
 
   virtual bool RecvInsertText(const uint64_t& aID,
                               const nsString& aText,
-                              const int32_t& aPosition) override;
+                              const int32_t& aPosition, bool* aValid) override;
 
   virtual bool RecvCopyText(const uint64_t& aID,
                             const int32_t& aStartPos,
-                            const int32_t& aEndPos) override;
+                            const int32_t& aEndPos, bool* aValid) override;
 
   virtual bool RecvCutText(const uint64_t& aID,
                            const int32_t& aStartPos,
-                           const int32_t& aEndPos) override;
+                           const int32_t& aEndPos, bool* aValid) override;
 
   virtual bool RecvDeleteText(const uint64_t& aID,
                               const int32_t& aStartPos,
-                              const int32_t& aEndPos) override;
+                              const int32_t& aEndPos, bool* aValid) override;
 
   virtual bool RecvPasteText(const uint64_t& aID,
-                             const int32_t& aPosition) override;
+                             const int32_t& aPosition, bool* aValid) override;
 
   virtual bool RecvImagePosition(const uint64_t& aID,
                                  const uint32_t& aCoordType,
diff --git a/accessible/ipc/PDocAccessible.ipdl b/accessible/ipc/PDocAccessible.ipdl
index 7127a1c4bbd5..689879254d80 100644
--- a/accessible/ipc/PDocAccessible.ipdl
+++ b/accessible/ipc/PDocAccessible.ipdl
@@ -82,7 +82,7 @@ child:
   prio(high) sync CharacterCount(uint64_t aID) returns(int32_t aCount);
   prio(high) sync SelectionCount(uint64_t aID) returns(int32_t aCount);
   prio(high) sync TextSubstring(uint64_t aID, int32_t aStartOffset, int32_t
-                                aEndOffset) returns(nsString aText);
+                                aEndOffset) returns(nsString aText, bool aValid);
   prio(high) sync GetTextAfterOffset(uint64_t aID, int32_t aOffset, int32_t aBoundaryType)
     returns(nsString aText, int32_t aStartOffset, int32_t aEndOffset);
   prio(high) sync GetTextAtOffset(uint64_t aID, int32_t aOffset, int32_t aBoundaryType)
@@ -124,11 +124,16 @@ child:
                          int32_t aX, int32_t aY);
 
   prio(high) sync ReplaceText(uint64_t aID, nsString aText);
-  prio(high) sync InsertText(uint64_t aID, nsString aText, int32_t aPosition);
-  prio(high) sync CopyText(uint64_t aID, int32_t aStartPos, int32_t aEndPos);
-  prio(high) sync CutText(uint64_t aID, int32_t aStartPos, int32_t aEndPos);
-  prio(high) sync DeleteText(uint64_t aID, int32_t aStartPos, int32_t aEndPos);
-  prio(high) sync PasteText(uint64_t aID, int32_t aPosition);
+  prio(high) sync InsertText(uint64_t aID, nsString aText, int32_t aPosition)
+    returns(bool aValid);
+  prio(high) sync CopyText(uint64_t aID, int32_t aStartPos, int32_t aEndPos)
+    returns(bool aValid);
+  prio(high) sync CutText(uint64_t aID, int32_t aStartPos, int32_t aEndPos)
+    returns(bool aValid);
+  prio(high) sync DeleteText(uint64_t aID, int32_t aStartPos, int32_t aEndPos)
+    returns(bool aValid);
+  prio(high) sync PasteText(uint64_t aID, int32_t aPosition)
+    returns(bool aValid);
 
   prio(high) sync ImagePosition(uint64_t aID, uint32_t aCoordType) returns(nsIntPoint aRetVal);
   prio(high) sync ImageSize(uint64_t aID) returns(IntSize aRetVal);
diff --git a/accessible/ipc/ProxyAccessible.cpp b/accessible/ipc/ProxyAccessible.cpp
index f2bf27df2857..be1bc1676736 100644
--- a/accessible/ipc/ProxyAccessible.cpp
+++ b/accessible/ipc/ProxyAccessible.cpp
@@ -181,11 +181,13 @@ ProxyAccessible::SelectionCount()
   return count;
 }
 
-void
+bool
 ProxyAccessible::TextSubstring(int32_t aStartOffset, int32_t aEndOfset,
                                nsString& aText) const
 {
-  unused << mDoc->SendTextSubstring(mID, aStartOffset, aEndOfset, &aText);
+  bool valid;
+  unused << mDoc->SendTextSubstring(mID, aStartOffset, aEndOfset, &aText, &valid);
+  return valid;
 }
 
 void
@@ -333,34 +335,44 @@ ProxyAccessible::ReplaceText(const nsString& aText)
   unused << mDoc->SendReplaceText(mID, aText);
 }
 
-void
+bool
 ProxyAccessible::InsertText(const nsString& aText, int32_t aPosition)
 {
-  unused << mDoc->SendInsertText(mID, aText, aPosition);
+  bool valid;
+  unused << mDoc->SendInsertText(mID, aText, aPosition, &valid);
+  return valid;
 }
 
-void
+bool
 ProxyAccessible::CopyText(int32_t aStartPos, int32_t aEndPos)
 {
-  unused << mDoc->SendCopyText(mID, aStartPos, aEndPos);
+  bool valid;
+  unused << mDoc->SendCopyText(mID, aStartPos, aEndPos, &valid);
+  return valid;
 }
 
-void
+bool
 ProxyAccessible::CutText(int32_t aStartPos, int32_t aEndPos)
 {
-  unused << mDoc->SendCutText(mID, aStartPos, aEndPos);
+  bool valid;
+  unused << mDoc->SendCutText(mID, aStartPos, aEndPos, &valid);
+  return valid;
 }
 
-void
+bool
 ProxyAccessible::DeleteText(int32_t aStartPos, int32_t aEndPos)
 {
-  unused << mDoc->SendDeleteText(mID, aStartPos, aEndPos);
+  bool valid;
+  unused << mDoc->SendDeleteText(mID, aStartPos, aEndPos, &valid);
+  return valid;
 }
 
-void
+bool
 ProxyAccessible::PasteText(int32_t aPosition)
 {
-  unused << mDoc->SendPasteText(mID, aPosition);
+  bool valid;
+  unused << mDoc->SendPasteText(mID, aPosition, &valid);
+  return valid;
 }
 
 nsIntPoint
diff --git a/accessible/ipc/ProxyAccessible.h b/accessible/ipc/ProxyAccessible.h
index 164a301c34a7..b9836b368a82 100644
--- a/accessible/ipc/ProxyAccessible.h
+++ b/accessible/ipc/ProxyAccessible.h
@@ -114,7 +114,7 @@ public:
   /**
    * Get the text between the given offsets.
    */
-  void TextSubstring(int32_t aStartOffset, int32_t aEndOfset,
+  bool TextSubstring(int32_t aStartOffset, int32_t aEndOfset,
                      nsString& aText) const;
 
   void GetTextAfterOffset(int32_t aOffset, AccessibleTextBoundary aBoundaryType,
@@ -169,15 +169,15 @@ public:
 
   void ReplaceText(const nsString& aText);
 
-  void InsertText(const nsString& aText, int32_t aPosition);
+  bool InsertText(const nsString& aText, int32_t aPosition);
 
-  void CopyText(int32_t aStartPos, int32_t aEndPos);
+  bool CopyText(int32_t aStartPos, int32_t aEndPos);
 
-  void CutText(int32_t aStartPos, int32_t aEndPos);
+  bool CutText(int32_t aStartPos, int32_t aEndPos);
 
-  void DeleteText(int32_t aStartPos, int32_t aEndPos);
+  bool DeleteText(int32_t aStartPos, int32_t aEndPos);
 
-  void PasteText(int32_t aPosition);
+  bool PasteText(int32_t aPosition);
 
   nsIntPoint ImagePosition(uint32_t aCoordType);
 
diff --git a/accessible/windows/ProxyWrappers.h b/accessible/windows/ProxyWrappers.h
new file mode 100644
index 000000000000..42aa00345176
--- /dev/null
+++ b/accessible/windows/ProxyWrappers.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. *
+ */
+
+#ifndef MOZILLA_A11Y_ProxyWrappers_h
+#define MOZILLA_A11Y_ProxyWrappers_h
+
+#include "HyperTextAccessible.h"
+
+namespace mozilla {
+namespace a11y {
+
+class ProxyAccessibleWrap : public AccessibleWrap
+{
+  public:
+  ProxyAccessibleWrap(ProxyAccessible* aProxy) :
+    AccessibleWrap(nullptr, nullptr)
+  {
+    mType = eProxyType;
+    mBits.proxy = aProxy;
+  }
+
+  virtual void Shutdown() override
+  {
+    mBits.proxy = nullptr;
+  }
+};
+
+class HyperTextProxyAccessibleWrap : public ProxyAccessibleWrap,
+                                     public ia2AccessibleEditableText,
+                                     public ia2AccessibleHypertext
+{
+  HyperTextProxyAccessibleWrap(ProxyAccessible* aProxy) :
+    ProxyAccessibleWrap(aProxy) {}
+};
+
+template<typename T>
+inline ProxyAccessible*
+HyperTextProxyFor(T* aWrapper)
+{
+  static_assert(mozilla::IsBaseOf<IUnknown, T>::value, "only IAccessible* should be passed in");
+  auto wrapper = static_cast<HyperTextProxyAccessibleWrap*>(aWrapper);
+  return wrapper->IsProxy() ? wrapper->Proxy() : nullptr;
+}
+
+}
+}
+
+#endif
diff --git a/accessible/windows/ia2/ia2Accessible.cpp b/accessible/windows/ia2/ia2Accessible.cpp
index b708300f050d..cd15a963c459 100644
--- a/accessible/windows/ia2/ia2Accessible.cpp
+++ b/accessible/windows/ia2/ia2Accessible.cpp
@@ -619,22 +619,7 @@ ia2Accessible::get_attributes(BSTR* aAttributes)
 
   nsTArray<Attribute> attrs;
   acc->Proxy()->Attributes(&attrs);
-  nsString attrStr;
-  size_t attrCount = attrs.Length();
-  for (size_t i = 0; i < attrCount; i++) {
-    EscapeAttributeChars(attrs[i].Name());
-    EscapeAttributeChars(attrs[i].Value());
-    AppendUTF8toUTF16(attrs[i].Name(), attrStr);
-    attrStr.Append(':');
-    attrStr.Append(attrs[i].Value());
-    attrStr.Append(';');
-  }
-
-  if (attrStr.IsEmpty())
-    return S_FALSE;
-
-  *aAttributes = ::SysAllocStringLen(attrStr.get(), attrStr.Length());
-  return *aAttributes ? S_OK : E_OUTOFMEMORY;
+  return ConvertToIA2Attributes(&attrs, aAttributes);
 
   A11Y_TRYBLOCK_END
 }
@@ -747,6 +732,28 @@ EscapeAttributeChars(String& aStr)
   }
 }
 
+HRESULT
+ia2Accessible::ConvertToIA2Attributes(nsTArray<Attribute>* aAttributes,
+                                      BSTR* aIA2Attributes)
+{
+  nsString attrStr;
+  size_t attrCount = aAttributes->Length();
+  for (size_t i = 0; i < attrCount; i++) {
+    EscapeAttributeChars(aAttributes->ElementAt(i).Name());
+    EscapeAttributeChars(aAttributes->ElementAt(i).Value());
+    AppendUTF8toUTF16(aAttributes->ElementAt(i).Name(), attrStr);
+    attrStr.Append(':');
+    attrStr.Append(aAttributes->ElementAt(i).Value());
+    attrStr.Append(';');
+  }
+
+  if (attrStr.IsEmpty())
+    return S_FALSE;
+
+  *aIA2Attributes = ::SysAllocStringLen(attrStr.get(), attrStr.Length());
+  return *aIA2Attributes ? S_OK : E_OUTOFMEMORY;
+}
+
 HRESULT
 ia2Accessible::ConvertToIA2Attributes(nsIPersistentProperties* aAttributes,
                                       BSTR* aIA2Attributes)
diff --git a/accessible/windows/ia2/ia2Accessible.h b/accessible/windows/ia2/ia2Accessible.h
index 7a14f960d8da..0dba1b953706 100644
--- a/accessible/windows/ia2/ia2Accessible.h
+++ b/accessible/windows/ia2/ia2Accessible.h
@@ -13,6 +13,7 @@
 
 namespace mozilla {
 namespace a11y {
+class Attribute;
 
 class ia2Accessible : public IAccessible2_2
 {
@@ -106,6 +107,8 @@ public:
   // Helper method
   static HRESULT ConvertToIA2Attributes(nsIPersistentProperties* aAttributes,
                                         BSTR* aIA2Attributes);
+  static HRESULT ConvertToIA2Attributes(nsTArray<Attribute>* aAttributes,
+                                        BSTR* aIA2Attributes);
 };
 
 } // namespace a11y
diff --git a/accessible/windows/ia2/ia2AccessibleEditableText.cpp b/accessible/windows/ia2/ia2AccessibleEditableText.cpp
index 668f6ff43f1c..4685a2df9756 100644
--- a/accessible/windows/ia2/ia2AccessibleEditableText.cpp
+++ b/accessible/windows/ia2/ia2AccessibleEditableText.cpp
@@ -10,6 +10,7 @@
 #include "AccessibleEditableText_i.c"
 #include "HyperTextAccessible-inl.h"
 #include "HyperTextAccessibleWrap.h"
+#include "ProxyWrappers.h"
 
 #include "nsCOMPtr.h"
 #include "nsString.h"
@@ -23,6 +24,10 @@ ia2AccessibleEditableText::copyText(long aStartOffset, long aEndOffset)
 {
   A11Y_TRYBLOCK_BEGIN
 
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    return proxy->CopyText(aStartOffset, aEndOffset) ? S_OK : E_INVALIDARG;
+  }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -41,6 +46,10 @@ ia2AccessibleEditableText::deleteText(long aStartOffset, long aEndOffset)
 {
   A11Y_TRYBLOCK_BEGIN
 
+    if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+      return proxy->DeleteText(aStartOffset, aEndOffset) ? S_OK : E_INVALIDARG;
+    }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -59,6 +68,12 @@ ia2AccessibleEditableText::insertText(long aOffset, BSTR *aText)
 {
   A11Y_TRYBLOCK_BEGIN
 
+  uint32_t length = ::SysStringLen(*aText);
+  nsAutoString text(*aText, length);
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    return proxy->InsertText(text, aOffset) ? S_OK : E_INVALIDARG;
+  }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -66,9 +81,6 @@ ia2AccessibleEditableText::insertText(long aOffset, BSTR *aText)
   if (!textAcc->IsValidOffset(aOffset))
     return E_INVALIDARG;
 
-  uint32_t length = ::SysStringLen(*aText);
-  nsAutoString text(*aText, length);
-
   textAcc->InsertText(text, aOffset);
   return S_OK;
 
@@ -80,6 +92,10 @@ ia2AccessibleEditableText::cutText(long aStartOffset, long aEndOffset)
 {
   A11Y_TRYBLOCK_BEGIN
 
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    return proxy->CutText(aStartOffset, aEndOffset) ? S_OK : E_INVALIDARG;
+  }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -98,6 +114,10 @@ ia2AccessibleEditableText::pasteText(long aOffset)
 {
   A11Y_TRYBLOCK_BEGIN
 
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    return proxy->PasteText(aOffset) ? S_OK : E_INVALIDARG;
+  }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
diff --git a/accessible/windows/ia2/ia2AccessibleText.cpp b/accessible/windows/ia2/ia2AccessibleText.cpp
index e5e8b54c0844..e0fbe3c759bd 100644
--- a/accessible/windows/ia2/ia2AccessibleText.cpp
+++ b/accessible/windows/ia2/ia2AccessibleText.cpp
@@ -12,6 +12,7 @@
 
 #include "HyperTextAccessibleWrap.h"
 #include "HyperTextAccessible-inl.h"
+#include "ProxyWrappers.h"
 
 using namespace mozilla::a11y;
 
@@ -22,6 +23,11 @@ ia2AccessibleText::addSelection(long aStartOffset, long aEndOffset)
 {
   A11Y_TRYBLOCK_BEGIN
 
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    return proxy->AddToSelection(aStartOffset, aEndOffset) ?
+      S_OK : E_INVALIDARG;
+  }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -45,16 +51,23 @@ ia2AccessibleText::get_attributes(long aOffset, long *aStartOffset,
   *aEndOffset = 0;
   *aTextAttributes = nullptr;
 
-  HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
-  if (textAcc->IsDefunct())
-    return CO_E_OBJNOTCONNECTED;
-
   int32_t startOffset = 0, endOffset = 0;
-  nsCOMPtr<nsIPersistentProperties> attributes =
-    textAcc->TextAttributes(true, aOffset, &startOffset, &endOffset);
+  HRESULT hr;
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    nsAutoTArray<Attribute, 10> attrs;
+    proxy->TextAttributes(true, aOffset, &attrs, &startOffset, &endOffset);
+    hr = AccessibleWrap::ConvertToIA2Attributes(&attrs, aTextAttributes);
+  } else {
+    HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
+    if (textAcc->IsDefunct())
+      return CO_E_OBJNOTCONNECTED;
+
+    nsCOMPtr<nsIPersistentProperties> attributes =
+      textAcc->TextAttributes(true, aOffset, &startOffset, &endOffset);
+
+    hr = AccessibleWrap::ConvertToIA2Attributes(attributes, aTextAttributes);
+  }
 
-  HRESULT hr = AccessibleWrap::ConvertToIA2Attributes(attributes,
-                                                      aTextAttributes);
   if (FAILED(hr))
     return hr;
 
@@ -76,11 +89,16 @@ ia2AccessibleText::get_caretOffset(long *aOffset)
 
   *aOffset = -1;
 
-  HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
-  if (textAcc->IsDefunct())
-    return CO_E_OBJNOTCONNECTED;
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    *aOffset = proxy->CaretOffset();
+  } else {
+    HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
+    if (textAcc->IsDefunct())
+      return CO_E_OBJNOTCONNECTED;
+
+    *aOffset = textAcc->CaretOffset();
+  }
 
-  *aOffset = textAcc->CaretOffset();
   return *aOffset != -1 ? S_OK : S_FALSE;
 
   A11Y_TRYBLOCK_END
@@ -98,15 +116,19 @@ ia2AccessibleText::get_characterExtents(long aOffset,
     return E_INVALIDARG;
   *aX = *aY = *aWidth = *aHeight = 0;
 
-  HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
-  if (textAcc->IsDefunct())
-    return CO_E_OBJNOTCONNECTED;
-
   uint32_t geckoCoordType = (aCoordType == IA2_COORDTYPE_SCREEN_RELATIVE) ?
     nsIAccessibleCoordinateType::COORDTYPE_SCREEN_RELATIVE :
     nsIAccessibleCoordinateType::COORDTYPE_PARENT_RELATIVE;
+  nsIntRect rect;
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    rect = proxy->CharBounds(aOffset, geckoCoordType);
+  } else {
+    HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
+    if (textAcc->IsDefunct())
+      return CO_E_OBJNOTCONNECTED;
 
-  nsIntRect rect = textAcc->CharBounds(aOffset, geckoCoordType);
+    rect = textAcc->CharBounds(aOffset, geckoCoordType);
+  }
 
   *aX = rect.x;
   *aY = rect.y;
@@ -126,11 +148,16 @@ ia2AccessibleText::get_nSelections(long* aNSelections)
     return E_INVALIDARG;
   *aNSelections = 0;
 
-  HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
-  if (textAcc->IsDefunct())
-    return CO_E_OBJNOTCONNECTED;
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    *aNSelections = proxy->SelectionCount();
+  } else {
+    HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
+    if (textAcc->IsDefunct())
+      return CO_E_OBJNOTCONNECTED;
+
+    *aNSelections = textAcc->SelectionCount();
+  }
 
-  *aNSelections = textAcc->SelectionCount();
   return S_OK;
 
   A11Y_TRYBLOCK_END
@@ -147,15 +174,20 @@ ia2AccessibleText::get_offsetAtPoint(long aX, long aY,
     return E_INVALIDARG;
   *aOffset = 0;
 
-  HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
-  if (textAcc->IsDefunct())
-    return CO_E_OBJNOTCONNECTED;
-
   uint32_t geckoCoordType = (aCoordType == IA2_COORDTYPE_SCREEN_RELATIVE) ?
     nsIAccessibleCoordinateType::COORDTYPE_SCREEN_RELATIVE :
     nsIAccessibleCoordinateType::COORDTYPE_PARENT_RELATIVE;
 
-  *aOffset = textAcc->OffsetAtPoint(aX, aY, geckoCoordType);
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    *aOffset = proxy->OffsetAtPoint(aX, aY, geckoCoordType);
+  } else {
+    HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
+    if (textAcc->IsDefunct())
+      return CO_E_OBJNOTCONNECTED;
+
+    *aOffset = textAcc->OffsetAtPoint(aX, aY, geckoCoordType);
+  }
+
   return *aOffset == -1 ? S_FALSE : S_OK;
 
   A11Y_TRYBLOCK_END
@@ -171,13 +203,20 @@ ia2AccessibleText::get_selection(long aSelectionIndex, long* aStartOffset,
     return E_INVALIDARG;
   *aStartOffset = *aEndOffset = 0;
 
-  HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
-  if (textAcc->IsDefunct())
-    return CO_E_OBJNOTCONNECTED;
-
   int32_t startOffset = 0, endOffset = 0;
-  if (!textAcc->SelectionBoundsAt(aSelectionIndex, &startOffset, &endOffset))
-    return E_INVALIDARG;
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    nsString unused;
+    if (!proxy->SelectionBoundsAt(aSelectionIndex, unused, &startOffset,
+                                  &endOffset))
+      return E_INVALIDARG;
+  } else {
+    HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
+    if (textAcc->IsDefunct())
+      return CO_E_OBJNOTCONNECTED;
+
+    if (!textAcc->SelectionBoundsAt(aSelectionIndex, &startOffset, &endOffset))
+      return E_INVALIDARG;
+  }
 
   *aStartOffset = startOffset;
   *aEndOffset = endOffset;
@@ -196,15 +235,22 @@ ia2AccessibleText::get_text(long aStartOffset, long aEndOffset, BSTR* aText)
 
   *aText = nullptr;
 
-  HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
-  if (textAcc->IsDefunct())
-    return CO_E_OBJNOTCONNECTED;
-
-  if (!textAcc->IsValidRange(aStartOffset, aEndOffset))
-    return E_INVALIDARG;
-
   nsAutoString text;
-  textAcc->TextSubstring(aStartOffset, aEndOffset, text);
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    if (!proxy->TextSubstring(aStartOffset, aEndOffset, text)) {
+      return E_INVALIDARG;
+    }
+  } else {
+    HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
+    if (textAcc->IsDefunct())
+      return CO_E_OBJNOTCONNECTED;
+
+    if (!textAcc->IsValidRange(aStartOffset, aEndOffset))
+      return E_INVALIDARG;
+
+    textAcc->TextSubstring(aStartOffset, aEndOffset, text);
+  }
+
   if (text.IsEmpty())
     return S_FALSE;
 
@@ -361,6 +407,10 @@ ia2AccessibleText::removeSelection(long aSelectionIndex)
 {
   A11Y_TRYBLOCK_BEGIN
 
+    if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+      return proxy->RemoveFromSelection(aSelectionIndex) ? S_OK : E_INVALIDARG;
+    }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -376,6 +426,10 @@ ia2AccessibleText::setCaretOffset(long aOffset)
 {
   A11Y_TRYBLOCK_BEGIN
 
+    if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+      return proxy->SetCaretOffset(aOffset) ? S_OK : E_INVALIDARG;
+    }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -395,6 +449,11 @@ ia2AccessibleText::setSelection(long aSelectionIndex, long aStartOffset,
 {
   A11Y_TRYBLOCK_BEGIN
 
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    return proxy->SetSelectionBoundsAt(aSelectionIndex, aStartOffset,
+                                       aEndOffset) ? S_OK : E_INVALIDARG;
+  }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -414,6 +473,11 @@ ia2AccessibleText::get_nCharacters(long* aNCharacters)
     return E_INVALIDARG;
   *aNCharacters = 0;
 
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    *aNCharacters = proxy->CharacterCount();
+    return S_OK;
+  }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -430,6 +494,11 @@ ia2AccessibleText::scrollSubstringTo(long aStartIndex, long aEndIndex,
 {
   A11Y_TRYBLOCK_BEGIN
 
+    if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+      proxy->ScrollSubstringTo(aStartIndex, aEndIndex, aScrollType);
+      return S_OK;
+    }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -450,6 +519,16 @@ ia2AccessibleText::scrollSubstringToPoint(long aStartIndex, long aEndIndex,
 {
   A11Y_TRYBLOCK_BEGIN
 
+  uint32_t geckoCoordType = (aCoordType == IA2_COORDTYPE_SCREEN_RELATIVE) ?
+    nsIAccessibleCoordinateType::COORDTYPE_SCREEN_RELATIVE :
+    nsIAccessibleCoordinateType::COORDTYPE_PARENT_RELATIVE;
+
+  if (ProxyAccessible* proxy = HyperTextProxyFor(this)) {
+    proxy->ScrollSubstringToPoint(aStartIndex, aEndIndex, geckoCoordType, aX,
+                                  aY);
+    return S_OK;
+  }
+
   HyperTextAccessible* textAcc = static_cast<HyperTextAccessibleWrap*>(this);
   if (textAcc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
@@ -457,10 +536,6 @@ ia2AccessibleText::scrollSubstringToPoint(long aStartIndex, long aEndIndex,
   if (!textAcc->IsValidRange(aStartIndex, aEndIndex))
     return E_INVALIDARG;
 
-  uint32_t geckoCoordType = (aCoordType == IA2_COORDTYPE_SCREEN_RELATIVE) ?
-    nsIAccessibleCoordinateType::COORDTYPE_SCREEN_RELATIVE :
-    nsIAccessibleCoordinateType::COORDTYPE_PARENT_RELATIVE;
-
   textAcc->ScrollSubstringToPoint(aStartIndex, aEndIndex,
                                   geckoCoordType, aX, aY);
   return S_OK;
diff --git a/accessible/windows/ia2/moz.build b/accessible/windows/ia2/moz.build
index 1b444004318f..7c593cf85f8a 100644
--- a/accessible/windows/ia2/moz.build
+++ b/accessible/windows/ia2/moz.build
@@ -39,6 +39,7 @@ LOCAL_INCLUDES += [
     '/accessible/base',
     '/accessible/generic',
     '/accessible/html',
+    '/accessible/windows',
     '/accessible/windows/msaa',
     '/accessible/xpcom',
     '/accessible/xul',
diff --git a/accessible/windows/msaa/Platform.cpp b/accessible/windows/msaa/Platform.cpp
index 9e7e6cf6a3e9..30f8a4dceed5 100644
--- a/accessible/windows/msaa/Platform.cpp
+++ b/accessible/windows/msaa/Platform.cpp
@@ -11,6 +11,7 @@
 #include "HyperTextAccessibleWrap.h"
 #include "nsWinUtils.h"
 #include "mozilla/a11y/ProxyAccessible.h"
+#include "ProxyWrappers.h"
 
 #include "mozilla/ClearOnShutdown.h"
 
@@ -35,22 +36,6 @@ a11y::PlatformShutdown()
   nsWinUtils::ShutdownWindowEmulation();
 }
 
-class ProxyAccessibleWrap : public AccessibleWrap
-{
-  public:
-  ProxyAccessibleWrap(ProxyAccessible* aProxy) :
-    AccessibleWrap(nullptr, nullptr)
-  {
-    mType = eProxyType;
-    mBits.proxy = aProxy;
-  }
-
-  virtual void Shutdown() override
-  {
-    mBits.proxy = nullptr;
-  }
-};
-
 void
 a11y::ProxyCreated(ProxyAccessible* aProxy, uint32_t)
 {
diff --git a/accessible/windows/msaa/moz.build b/accessible/windows/msaa/moz.build
index dc88de688b79..804f2b4c2fd7 100644
--- a/accessible/windows/msaa/moz.build
+++ b/accessible/windows/msaa/moz.build
@@ -48,6 +48,7 @@ LOCAL_INCLUDES += [
     '/accessible/base',
     '/accessible/generic',
     '/accessible/html',
+    '/accessible/windows',
     '/accessible/windows/ia2',
     '/accessible/windows/sdn',
     '/accessible/windows/uia',