diff --git a/mozilla/layout/generic/nsBlockFrame.cpp b/mozilla/layout/generic/nsBlockFrame.cpp
index eeb1f6a5ba6..6d169f06aa4 100644
--- a/mozilla/layout/generic/nsBlockFrame.cpp
+++ b/mozilla/layout/generic/nsBlockFrame.cpp
@@ -20,7 +20,6 @@
  * Contributor(s): 
  *   Steve Clark <buster@netscape.com>
  *   Robert O'Callahan <roc+moz@cs.cmu.edu>
- *   Pierre Phaneuf <pp@ludusdesign.com>
  */
 #include "nsCOMPtr.h"
 #include "nsBlockFrame.h"
@@ -1206,7 +1205,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = (void*) tmp;
     return NS_OK;
   }
-  if (aIID.Equals(NS_GET_IID(nsILineIterator))) {
+  if ( aIID.Equals(NS_GET_IID(nsILineIterator)) || aIID.Equals(NS_GET_IID(nsILineIteratorNavigator)) )
+  {
     nsLineIterator* it = new nsLineIterator;
     if (!it) {
       *aInstancePtr = nsnull;
@@ -1220,7 +1220,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
       delete it;
       return rv;
     }
-    return it->QueryInterface(aIID, aInstancePtr);
+    NS_ADDREF((nsILineIterator *) (*aInstancePtr = (void *) it));
+    return NS_OK;
   }
   return nsBlockFrameSuper::QueryInterface(aIID, aInstancePtr);
 }
diff --git a/mozilla/layout/generic/nsBlockReflowState.cpp b/mozilla/layout/generic/nsBlockReflowState.cpp
index eeb1f6a5ba6..6d169f06aa4 100644
--- a/mozilla/layout/generic/nsBlockReflowState.cpp
+++ b/mozilla/layout/generic/nsBlockReflowState.cpp
@@ -20,7 +20,6 @@
  * Contributor(s): 
  *   Steve Clark <buster@netscape.com>
  *   Robert O'Callahan <roc+moz@cs.cmu.edu>
- *   Pierre Phaneuf <pp@ludusdesign.com>
  */
 #include "nsCOMPtr.h"
 #include "nsBlockFrame.h"
@@ -1206,7 +1205,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = (void*) tmp;
     return NS_OK;
   }
-  if (aIID.Equals(NS_GET_IID(nsILineIterator))) {
+  if ( aIID.Equals(NS_GET_IID(nsILineIterator)) || aIID.Equals(NS_GET_IID(nsILineIteratorNavigator)) )
+  {
     nsLineIterator* it = new nsLineIterator;
     if (!it) {
       *aInstancePtr = nsnull;
@@ -1220,7 +1220,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
       delete it;
       return rv;
     }
-    return it->QueryInterface(aIID, aInstancePtr);
+    NS_ADDREF((nsILineIterator *) (*aInstancePtr = (void *) it));
+    return NS_OK;
   }
   return nsBlockFrameSuper::QueryInterface(aIID, aInstancePtr);
 }
diff --git a/mozilla/layout/generic/nsBlockReflowState.h b/mozilla/layout/generic/nsBlockReflowState.h
index eeb1f6a5ba6..6d169f06aa4 100644
--- a/mozilla/layout/generic/nsBlockReflowState.h
+++ b/mozilla/layout/generic/nsBlockReflowState.h
@@ -20,7 +20,6 @@
  * Contributor(s): 
  *   Steve Clark <buster@netscape.com>
  *   Robert O'Callahan <roc+moz@cs.cmu.edu>
- *   Pierre Phaneuf <pp@ludusdesign.com>
  */
 #include "nsCOMPtr.h"
 #include "nsBlockFrame.h"
@@ -1206,7 +1205,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = (void*) tmp;
     return NS_OK;
   }
-  if (aIID.Equals(NS_GET_IID(nsILineIterator))) {
+  if ( aIID.Equals(NS_GET_IID(nsILineIterator)) || aIID.Equals(NS_GET_IID(nsILineIteratorNavigator)) )
+  {
     nsLineIterator* it = new nsLineIterator;
     if (!it) {
       *aInstancePtr = nsnull;
@@ -1220,7 +1220,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
       delete it;
       return rv;
     }
-    return it->QueryInterface(aIID, aInstancePtr);
+    NS_ADDREF((nsILineIterator *) (*aInstancePtr = (void *) it));
+    return NS_OK;
   }
   return nsBlockFrameSuper::QueryInterface(aIID, aInstancePtr);
 }
diff --git a/mozilla/layout/generic/nsFrame.cpp b/mozilla/layout/generic/nsFrame.cpp
index bdc0f29621a..88db2de7f2a 100644
--- a/mozilla/layout/generic/nsFrame.cpp
+++ b/mozilla/layout/generic/nsFrame.cpp
@@ -2277,8 +2277,8 @@ nsFrame::GetNextPrevLineFromeBlockFrame(nsIPresContext* aPresContext,
   aPos->mPreferLeft = (aPos->mDirection == eDirNext);
 
    nsresult result;
-  nsCOMPtr<nsILineIterator> it; 
-  result = aBlockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+  nsCOMPtr<nsILineIteratorNavigator> it; 
+  result = aBlockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
   if (NS_FAILED(result) || !it)
     return result;
   PRInt32 searchingLine = aLineStart;
@@ -2351,9 +2351,9 @@ nsFrame::GetNextPrevLineFromeBlockFrame(nsIPresContext* aPresContext,
 
     if (NS_SUCCEEDED(result) && resultFrame)
     {
-      nsCOMPtr<nsILineIterator> newIt; 
+      nsCOMPtr<nsILineIteratorNavigator> newIt; 
       //check to see if this is ANOTHER blockframe inside the other one if so then call into its lines
-      result = resultFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(newIt));
+      result = resultFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(newIt));
       if (NS_SUCCEEDED(result) && newIt)
       {
         aPos->mResultFrame = resultFrame;
@@ -2538,7 +2538,7 @@ nsFrame::PeekOffset(nsIPresContext* aPresContext, nsPeekOffsetStruct *aPos)
     }break;
     case eSelectLine :
     {
-      nsCOMPtr<nsILineIterator> it; 
+      nsCOMPtr<nsILineIteratorNavigator> it; 
       nsIFrame *blockFrame = this;
       nsIFrame *thisBlock = this;
       PRInt32   thisLine;
@@ -2548,13 +2548,13 @@ nsFrame::PeekOffset(nsIPresContext* aPresContext, nsPeekOffsetStruct *aPos)
         result = blockFrame->GetParent(&blockFrame);
         if (NS_FAILED(result) || !blockFrame) //if at line 0 then nothing to do
           return result;
-        result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+        result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
         while (NS_FAILED(result) && blockFrame)
         {
           thisBlock = blockFrame;
           result = blockFrame->GetParent(&blockFrame);
           if (NS_SUCCEEDED(result) && blockFrame){
-            result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+            result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
           }
         }
         //this block is now one child down from blockframe
@@ -2586,7 +2586,7 @@ nsFrame::PeekOffset(nsIPresContext* aPresContext, nsPeekOffsetStruct *aPos)
           else
             doneLooping = PR_TRUE; //do not continue with while loop
           if (NS_SUCCEEDED(result) && aPos->mResultFrame){
-            result = aPos->mResultFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+            result = aPos->mResultFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
             if (NS_SUCCEEDED(result) && it)//we have struck another block element!
             {
               doneLooping = PR_FALSE;
@@ -2610,20 +2610,20 @@ nsFrame::PeekOffset(nsIPresContext* aPresContext, nsPeekOffsetStruct *aPos)
     case eSelectBeginLine:
     case eSelectEndLine:
     {
-      nsCOMPtr<nsILineIterator> it; 
+      nsCOMPtr<nsILineIteratorNavigator> it; 
       nsIFrame *blockFrame = this;
       nsIFrame *thisBlock = this;
       PRInt32   thisLine;
       result = blockFrame->GetParent(&blockFrame);
       if (NS_FAILED(result) || !blockFrame) //if at line 0 then nothing to do
         return result;
-      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
       while (NS_FAILED(result) && blockFrame)
       {
         thisBlock = blockFrame;
         result = blockFrame->GetParent(&blockFrame);
         if (NS_SUCCEEDED(result) && blockFrame){
-          result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+          result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
         }
       }
       //this block is now one child down from blockframe
@@ -2710,14 +2710,14 @@ nsFrame::GetLineNumber(nsIFrame *aFrame)
   nsIFrame *blockFrame = aFrame;
   nsIFrame *thisBlock;
   PRInt32   thisLine;
-  nsCOMPtr<nsILineIterator> it; 
+  nsCOMPtr<nsILineIteratorNavigator> it; 
   nsresult result = NS_ERROR_FAILURE;
   while (NS_FAILED(result) && blockFrame)
   {
     thisBlock = blockFrame;
     result = blockFrame->GetParent(&blockFrame);
     if (NS_SUCCEEDED(result) && blockFrame){
-      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
     }
     else
       blockFrame = nsnull;
@@ -2740,14 +2740,14 @@ nsFrame::GetFrameFromDirection(nsIPresContext* aPresContext, nsPeekOffsetStruct
   nsIFrame *blockFrame = this;
   nsIFrame *thisBlock;
   PRInt32   thisLine;
-  nsCOMPtr<nsILineIterator> it; 
+  nsCOMPtr<nsILineIteratorNavigator> it; 
   nsresult result = NS_ERROR_FAILURE;
   while (NS_FAILED(result) && blockFrame)
   {
     thisBlock = blockFrame;
     result = blockFrame->GetParent(&blockFrame);
     if (NS_SUCCEEDED(result) && blockFrame){
-      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
     }
     else
       blockFrame = nsnull;
diff --git a/mozilla/layout/generic/nsILineIterator.h b/mozilla/layout/generic/nsILineIterator.h
index 6895a9fd921..b868c87190a 100644
--- a/mozilla/layout/generic/nsILineIterator.h
+++ b/mozilla/layout/generic/nsILineIterator.h
@@ -28,6 +28,10 @@
 #define NS_ILINE_ITERATOR_IID \
  { 0xa6cf90ff, 0x15b3, 0x11d2,{0x93, 0x2e, 0x00, 0x80, 0x5f, 0x8a, 0xdd, 0x32}}
 
+/* {80AA3D7A-E0BF-4e18-8A82-2110397D7BC4}*/
+#define NS_ILINE_ITERATOR_NAV_IID \
+ { 0x80aa3d7a, 0xe0bf, 0x4e18,{0x8a, 0x82, 0x21, 0x10, 0x39, 0x7d, 0x7b, 0xc4}}
+
 // Line iterator API.
 //
 // Lines are numbered from 0 to N, where 0 is the top line and N is
@@ -114,4 +118,10 @@ public:
   NS_IMETHOD GetNextSibling(nsIFrame*& aFrame, PRInt32 aLineNumber) = 0;
 };
 
+//special line iterator for keyboard navigation
+class nsILineIteratorNavigator : public nsILineIterator {
+public:
+  NS_DEFINE_STATIC_IID_ACCESSOR(NS_ILINE_ITERATOR_NAV_IID)
+
+};
 #endif /* nsILineIterator_h___ */
diff --git a/mozilla/layout/generic/nsLineBox.cpp b/mozilla/layout/generic/nsLineBox.cpp
index 5fbbc5e7bb1..49f70039dfa 100644
--- a/mozilla/layout/generic/nsLineBox.cpp
+++ b/mozilla/layout/generic/nsLineBox.cpp
@@ -516,7 +516,7 @@ nsLineIterator::~nsLineIterator()
   }
 }
 
-NS_IMPL_ISUPPORTS(nsLineIterator, kILineIteratorIID)
+NS_IMPL_ISUPPORTS2(nsLineIterator, nsILineIterator, nsILineIteratorNavigator)
 
 nsresult
 nsLineIterator::Init(nsLineBox* aLines, PRBool aRightToLeft)
diff --git a/mozilla/layout/generic/nsLineBox.h b/mozilla/layout/generic/nsLineBox.h
index 840267dc9ca..df25c4fb4d6 100644
--- a/mozilla/layout/generic/nsLineBox.h
+++ b/mozilla/layout/generic/nsLineBox.h
@@ -371,7 +371,7 @@ protected:
 
 //----------------------------------------------------------------------
 
-class nsLineIterator : public nsILineIterator {
+class nsLineIterator : public nsILineIteratorNavigator {
 public:
   nsLineIterator();
   virtual ~nsLineIterator();
diff --git a/mozilla/layout/html/base/src/nsBlockFrame.cpp b/mozilla/layout/html/base/src/nsBlockFrame.cpp
index eeb1f6a5ba6..6d169f06aa4 100644
--- a/mozilla/layout/html/base/src/nsBlockFrame.cpp
+++ b/mozilla/layout/html/base/src/nsBlockFrame.cpp
@@ -20,7 +20,6 @@
  * Contributor(s): 
  *   Steve Clark <buster@netscape.com>
  *   Robert O'Callahan <roc+moz@cs.cmu.edu>
- *   Pierre Phaneuf <pp@ludusdesign.com>
  */
 #include "nsCOMPtr.h"
 #include "nsBlockFrame.h"
@@ -1206,7 +1205,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = (void*) tmp;
     return NS_OK;
   }
-  if (aIID.Equals(NS_GET_IID(nsILineIterator))) {
+  if ( aIID.Equals(NS_GET_IID(nsILineIterator)) || aIID.Equals(NS_GET_IID(nsILineIteratorNavigator)) )
+  {
     nsLineIterator* it = new nsLineIterator;
     if (!it) {
       *aInstancePtr = nsnull;
@@ -1220,7 +1220,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
       delete it;
       return rv;
     }
-    return it->QueryInterface(aIID, aInstancePtr);
+    NS_ADDREF((nsILineIterator *) (*aInstancePtr = (void *) it));
+    return NS_OK;
   }
   return nsBlockFrameSuper::QueryInterface(aIID, aInstancePtr);
 }
diff --git a/mozilla/layout/html/base/src/nsBlockReflowState.cpp b/mozilla/layout/html/base/src/nsBlockReflowState.cpp
index eeb1f6a5ba6..6d169f06aa4 100644
--- a/mozilla/layout/html/base/src/nsBlockReflowState.cpp
+++ b/mozilla/layout/html/base/src/nsBlockReflowState.cpp
@@ -20,7 +20,6 @@
  * Contributor(s): 
  *   Steve Clark <buster@netscape.com>
  *   Robert O'Callahan <roc+moz@cs.cmu.edu>
- *   Pierre Phaneuf <pp@ludusdesign.com>
  */
 #include "nsCOMPtr.h"
 #include "nsBlockFrame.h"
@@ -1206,7 +1205,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = (void*) tmp;
     return NS_OK;
   }
-  if (aIID.Equals(NS_GET_IID(nsILineIterator))) {
+  if ( aIID.Equals(NS_GET_IID(nsILineIterator)) || aIID.Equals(NS_GET_IID(nsILineIteratorNavigator)) )
+  {
     nsLineIterator* it = new nsLineIterator;
     if (!it) {
       *aInstancePtr = nsnull;
@@ -1220,7 +1220,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
       delete it;
       return rv;
     }
-    return it->QueryInterface(aIID, aInstancePtr);
+    NS_ADDREF((nsILineIterator *) (*aInstancePtr = (void *) it));
+    return NS_OK;
   }
   return nsBlockFrameSuper::QueryInterface(aIID, aInstancePtr);
 }
diff --git a/mozilla/layout/html/base/src/nsBlockReflowState.h b/mozilla/layout/html/base/src/nsBlockReflowState.h
index eeb1f6a5ba6..6d169f06aa4 100644
--- a/mozilla/layout/html/base/src/nsBlockReflowState.h
+++ b/mozilla/layout/html/base/src/nsBlockReflowState.h
@@ -20,7 +20,6 @@
  * Contributor(s): 
  *   Steve Clark <buster@netscape.com>
  *   Robert O'Callahan <roc+moz@cs.cmu.edu>
- *   Pierre Phaneuf <pp@ludusdesign.com>
  */
 #include "nsCOMPtr.h"
 #include "nsBlockFrame.h"
@@ -1206,7 +1205,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = (void*) tmp;
     return NS_OK;
   }
-  if (aIID.Equals(NS_GET_IID(nsILineIterator))) {
+  if ( aIID.Equals(NS_GET_IID(nsILineIterator)) || aIID.Equals(NS_GET_IID(nsILineIteratorNavigator)) )
+  {
     nsLineIterator* it = new nsLineIterator;
     if (!it) {
       *aInstancePtr = nsnull;
@@ -1220,7 +1220,8 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
       delete it;
       return rv;
     }
-    return it->QueryInterface(aIID, aInstancePtr);
+    NS_ADDREF((nsILineIterator *) (*aInstancePtr = (void *) it));
+    return NS_OK;
   }
   return nsBlockFrameSuper::QueryInterface(aIID, aInstancePtr);
 }
diff --git a/mozilla/layout/html/base/src/nsFrame.cpp b/mozilla/layout/html/base/src/nsFrame.cpp
index bdc0f29621a..88db2de7f2a 100644
--- a/mozilla/layout/html/base/src/nsFrame.cpp
+++ b/mozilla/layout/html/base/src/nsFrame.cpp
@@ -2277,8 +2277,8 @@ nsFrame::GetNextPrevLineFromeBlockFrame(nsIPresContext* aPresContext,
   aPos->mPreferLeft = (aPos->mDirection == eDirNext);
 
    nsresult result;
-  nsCOMPtr<nsILineIterator> it; 
-  result = aBlockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+  nsCOMPtr<nsILineIteratorNavigator> it; 
+  result = aBlockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
   if (NS_FAILED(result) || !it)
     return result;
   PRInt32 searchingLine = aLineStart;
@@ -2351,9 +2351,9 @@ nsFrame::GetNextPrevLineFromeBlockFrame(nsIPresContext* aPresContext,
 
     if (NS_SUCCEEDED(result) && resultFrame)
     {
-      nsCOMPtr<nsILineIterator> newIt; 
+      nsCOMPtr<nsILineIteratorNavigator> newIt; 
       //check to see if this is ANOTHER blockframe inside the other one if so then call into its lines
-      result = resultFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(newIt));
+      result = resultFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(newIt));
       if (NS_SUCCEEDED(result) && newIt)
       {
         aPos->mResultFrame = resultFrame;
@@ -2538,7 +2538,7 @@ nsFrame::PeekOffset(nsIPresContext* aPresContext, nsPeekOffsetStruct *aPos)
     }break;
     case eSelectLine :
     {
-      nsCOMPtr<nsILineIterator> it; 
+      nsCOMPtr<nsILineIteratorNavigator> it; 
       nsIFrame *blockFrame = this;
       nsIFrame *thisBlock = this;
       PRInt32   thisLine;
@@ -2548,13 +2548,13 @@ nsFrame::PeekOffset(nsIPresContext* aPresContext, nsPeekOffsetStruct *aPos)
         result = blockFrame->GetParent(&blockFrame);
         if (NS_FAILED(result) || !blockFrame) //if at line 0 then nothing to do
           return result;
-        result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+        result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
         while (NS_FAILED(result) && blockFrame)
         {
           thisBlock = blockFrame;
           result = blockFrame->GetParent(&blockFrame);
           if (NS_SUCCEEDED(result) && blockFrame){
-            result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+            result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
           }
         }
         //this block is now one child down from blockframe
@@ -2586,7 +2586,7 @@ nsFrame::PeekOffset(nsIPresContext* aPresContext, nsPeekOffsetStruct *aPos)
           else
             doneLooping = PR_TRUE; //do not continue with while loop
           if (NS_SUCCEEDED(result) && aPos->mResultFrame){
-            result = aPos->mResultFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+            result = aPos->mResultFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
             if (NS_SUCCEEDED(result) && it)//we have struck another block element!
             {
               doneLooping = PR_FALSE;
@@ -2610,20 +2610,20 @@ nsFrame::PeekOffset(nsIPresContext* aPresContext, nsPeekOffsetStruct *aPos)
     case eSelectBeginLine:
     case eSelectEndLine:
     {
-      nsCOMPtr<nsILineIterator> it; 
+      nsCOMPtr<nsILineIteratorNavigator> it; 
       nsIFrame *blockFrame = this;
       nsIFrame *thisBlock = this;
       PRInt32   thisLine;
       result = blockFrame->GetParent(&blockFrame);
       if (NS_FAILED(result) || !blockFrame) //if at line 0 then nothing to do
         return result;
-      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
       while (NS_FAILED(result) && blockFrame)
       {
         thisBlock = blockFrame;
         result = blockFrame->GetParent(&blockFrame);
         if (NS_SUCCEEDED(result) && blockFrame){
-          result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+          result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
         }
       }
       //this block is now one child down from blockframe
@@ -2710,14 +2710,14 @@ nsFrame::GetLineNumber(nsIFrame *aFrame)
   nsIFrame *blockFrame = aFrame;
   nsIFrame *thisBlock;
   PRInt32   thisLine;
-  nsCOMPtr<nsILineIterator> it; 
+  nsCOMPtr<nsILineIteratorNavigator> it; 
   nsresult result = NS_ERROR_FAILURE;
   while (NS_FAILED(result) && blockFrame)
   {
     thisBlock = blockFrame;
     result = blockFrame->GetParent(&blockFrame);
     if (NS_SUCCEEDED(result) && blockFrame){
-      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
     }
     else
       blockFrame = nsnull;
@@ -2740,14 +2740,14 @@ nsFrame::GetFrameFromDirection(nsIPresContext* aPresContext, nsPeekOffsetStruct
   nsIFrame *blockFrame = this;
   nsIFrame *thisBlock;
   PRInt32   thisLine;
-  nsCOMPtr<nsILineIterator> it; 
+  nsCOMPtr<nsILineIteratorNavigator> it; 
   nsresult result = NS_ERROR_FAILURE;
   while (NS_FAILED(result) && blockFrame)
   {
     thisBlock = blockFrame;
     result = blockFrame->GetParent(&blockFrame);
     if (NS_SUCCEEDED(result) && blockFrame){
-      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIterator),getter_AddRefs(it));
+      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
     }
     else
       blockFrame = nsnull;
diff --git a/mozilla/layout/html/base/src/nsILineIterator.h b/mozilla/layout/html/base/src/nsILineIterator.h
index 6895a9fd921..b868c87190a 100644
--- a/mozilla/layout/html/base/src/nsILineIterator.h
+++ b/mozilla/layout/html/base/src/nsILineIterator.h
@@ -28,6 +28,10 @@
 #define NS_ILINE_ITERATOR_IID \
  { 0xa6cf90ff, 0x15b3, 0x11d2,{0x93, 0x2e, 0x00, 0x80, 0x5f, 0x8a, 0xdd, 0x32}}
 
+/* {80AA3D7A-E0BF-4e18-8A82-2110397D7BC4}*/
+#define NS_ILINE_ITERATOR_NAV_IID \
+ { 0x80aa3d7a, 0xe0bf, 0x4e18,{0x8a, 0x82, 0x21, 0x10, 0x39, 0x7d, 0x7b, 0xc4}}
+
 // Line iterator API.
 //
 // Lines are numbered from 0 to N, where 0 is the top line and N is
@@ -114,4 +118,10 @@ public:
   NS_IMETHOD GetNextSibling(nsIFrame*& aFrame, PRInt32 aLineNumber) = 0;
 };
 
+//special line iterator for keyboard navigation
+class nsILineIteratorNavigator : public nsILineIterator {
+public:
+  NS_DEFINE_STATIC_IID_ACCESSOR(NS_ILINE_ITERATOR_NAV_IID)
+
+};
 #endif /* nsILineIterator_h___ */
diff --git a/mozilla/layout/html/base/src/nsLineBox.cpp b/mozilla/layout/html/base/src/nsLineBox.cpp
index 5fbbc5e7bb1..49f70039dfa 100644
--- a/mozilla/layout/html/base/src/nsLineBox.cpp
+++ b/mozilla/layout/html/base/src/nsLineBox.cpp
@@ -516,7 +516,7 @@ nsLineIterator::~nsLineIterator()
   }
 }
 
-NS_IMPL_ISUPPORTS(nsLineIterator, kILineIteratorIID)
+NS_IMPL_ISUPPORTS2(nsLineIterator, nsILineIterator, nsILineIteratorNavigator)
 
 nsresult
 nsLineIterator::Init(nsLineBox* aLines, PRBool aRightToLeft)
diff --git a/mozilla/layout/html/base/src/nsLineBox.h b/mozilla/layout/html/base/src/nsLineBox.h
index 840267dc9ca..df25c4fb4d6 100644
--- a/mozilla/layout/html/base/src/nsLineBox.h
+++ b/mozilla/layout/html/base/src/nsLineBox.h
@@ -371,7 +371,7 @@ protected:
 
 //----------------------------------------------------------------------
 
-class nsLineIterator : public nsILineIterator {
+class nsLineIterator : public nsILineIteratorNavigator {
 public:
   nsLineIterator();
   virtual ~nsLineIterator();
diff --git a/mozilla/layout/html/table/src/nsTableRowGroupFrame.cpp b/mozilla/layout/html/table/src/nsTableRowGroupFrame.cpp
index 4523796fd52..0f28563cada 100644
--- a/mozilla/layout/html/table/src/nsTableRowGroupFrame.cpp
+++ b/mozilla/layout/html/table/src/nsTableRowGroupFrame.cpp
@@ -65,9 +65,9 @@ nsTableRowGroupFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = (void*)this;
     return NS_OK;
   }
-  else if (aIID.Equals(NS_GET_IID(nsILineIterator))) 
+  else if (aIID.Equals(NS_GET_IID(nsILineIteratorNavigator))) 
   { // note there is no addref here, frames are not addref'd
-    *aInstancePtr = (void*)(nsILineIterator*)this;
+    *aInstancePtr = (void*)(nsILineIteratorNavigator*)this;
     return NS_OK;
   }
   else {
diff --git a/mozilla/layout/html/table/src/nsTableRowGroupFrame.h b/mozilla/layout/html/table/src/nsTableRowGroupFrame.h
index d38d653947d..cbb1b065076 100644
--- a/mozilla/layout/html/table/src/nsTableRowGroupFrame.h
+++ b/mozilla/layout/html/table/src/nsTableRowGroupFrame.h
@@ -83,7 +83,7 @@ struct RowGroupReflowState {
  * @see nsTableFrame
  * @see nsTableRowFrame
  */
-class nsTableRowGroupFrame : public nsHTMLContainerFrame, public nsILineIterator
+class nsTableRowGroupFrame : public nsHTMLContainerFrame, public nsILineIteratorNavigator
 {
 public:
   // nsISupports
diff --git a/mozilla/layout/tables/nsTableRowGroupFrame.cpp b/mozilla/layout/tables/nsTableRowGroupFrame.cpp
index 4523796fd52..0f28563cada 100644
--- a/mozilla/layout/tables/nsTableRowGroupFrame.cpp
+++ b/mozilla/layout/tables/nsTableRowGroupFrame.cpp
@@ -65,9 +65,9 @@ nsTableRowGroupFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = (void*)this;
     return NS_OK;
   }
-  else if (aIID.Equals(NS_GET_IID(nsILineIterator))) 
+  else if (aIID.Equals(NS_GET_IID(nsILineIteratorNavigator))) 
   { // note there is no addref here, frames are not addref'd
-    *aInstancePtr = (void*)(nsILineIterator*)this;
+    *aInstancePtr = (void*)(nsILineIteratorNavigator*)this;
     return NS_OK;
   }
   else {
diff --git a/mozilla/layout/tables/nsTableRowGroupFrame.h b/mozilla/layout/tables/nsTableRowGroupFrame.h
index d38d653947d..cbb1b065076 100644
--- a/mozilla/layout/tables/nsTableRowGroupFrame.h
+++ b/mozilla/layout/tables/nsTableRowGroupFrame.h
@@ -83,7 +83,7 @@ struct RowGroupReflowState {
  * @see nsTableFrame
  * @see nsTableRowFrame
  */
-class nsTableRowGroupFrame : public nsHTMLContainerFrame, public nsILineIterator
+class nsTableRowGroupFrame : public nsHTMLContainerFrame, public nsILineIteratorNavigator
 {
 public:
   // nsISupports