diff --git a/layout/generic/nsBRFrame.cpp b/layout/generic/nsBRFrame.cpp
index 13d501553d1..5144155de95 100644
--- a/layout/generic/nsBRFrame.cpp
+++ b/layout/generic/nsBRFrame.cpp
@@ -84,7 +84,8 @@ public:
 
   virtual PRBool IsFrameOfType(PRUint32 aFlags) const
   {
-    return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eReplaced));
+    return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eReplaced |
+                                             nsIFrame::eLineParticipant));
   }
 
 #ifdef ACCESSIBILITY  
diff --git a/layout/generic/nsBlockReflowContext.cpp b/layout/generic/nsBlockReflowContext.cpp
index d1eefd23bb1..ad46e9ae510 100644
--- a/layout/generic/nsBlockReflowContext.cpp
+++ b/layout/generic/nsBlockReflowContext.cpp
@@ -277,7 +277,6 @@ nsBlockReflowContext::ReflowBlock(const nsRect&       aSpace,
     }
   }
 
-  aFrameRS.mLineLayout = nsnull;
   if (!aIsAdjacentWithTop) {
     aFrameRS.mFlags.mIsTopOfPage = PR_FALSE;  // make sure this is cleared
   }
diff --git a/layout/generic/nsFirstLetterFrame.cpp b/layout/generic/nsFirstLetterFrame.cpp
index daf60ac7a90..a1729a01833 100644
--- a/layout/generic/nsFirstLetterFrame.cpp
+++ b/layout/generic/nsFirstLetterFrame.cpp
@@ -66,6 +66,8 @@ public:
 
   virtual PRBool IsFrameOfType(PRUint32 aFlags) const
   {
+    if (!GetStyleDisplay()->IsFloating())
+      aFlags = aFlags & ~(nsIFrame::eLineParticipant);
     return nsFirstLetterFrameSuper::IsFrameOfType(aFlags &
       ~(nsIFrame::eBidiInlineContainer));
   }
diff --git a/layout/generic/nsHTMLReflowState.cpp b/layout/generic/nsHTMLReflowState.cpp
index 959d7d007de..a46d68371fe 100644
--- a/layout/generic/nsHTMLReflowState.cpp
+++ b/layout/generic/nsHTMLReflowState.cpp
@@ -158,7 +158,10 @@ nsHTMLReflowState::nsHTMLReflowState(nsPresContext*           aPresContext,
   availableHeight = aAvailableSpace.height;
 
   mSpaceManager = aParentReflowState.mSpaceManager;
-  mLineLayout = aParentReflowState.mLineLayout;
+  if (frame->IsFrameOfType(nsIFrame::eLineParticipant))
+    mLineLayout = aParentReflowState.mLineLayout;
+  else
+    mLineLayout = nsnull;
   mFlags.mIsTopOfPage = aParentReflowState.mFlags.mIsTopOfPage;
   mFlags.mNextInFlowUntouched = aParentReflowState.mFlags.mNextInFlowUntouched &&
     CheckNextInFlowParenthood(aFrame, aParentReflowState.frame);
diff --git a/layout/generic/nsIFrame.h b/layout/generic/nsIFrame.h
index b680a54d9b0..b6ba987ef1e 100644
--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@@ -1435,6 +1435,9 @@ public:
     // Frame that contains a block but looks like a replaced element
     // from the outside
     eReplacedContainsBlock =            1 << 5,
+    // A frame that participates in inline reflow, i.e., one that
+    // requires nsHTMLReflowState::mLineLayout.
+    eLineParticipant =                  1 << 6,
 
 
     // These are to allow nsFrame::Init to assert that IsFrameOfType
diff --git a/layout/generic/nsInlineFrame.h b/layout/generic/nsInlineFrame.h
index f771905ae43..c56e8f1e43d 100644
--- a/layout/generic/nsInlineFrame.h
+++ b/layout/generic/nsInlineFrame.h
@@ -103,7 +103,7 @@ public:
   virtual PRBool IsFrameOfType(PRUint32 aFlags) const
   {
     return nsInlineFrameSuper::IsFrameOfType(aFlags &
-      ~(nsIFrame::eBidiInlineContainer));
+      ~(nsIFrame::eBidiInlineContainer | nsIFrame::eLineParticipant));
   }
 
   virtual PRBool IsEmpty();
diff --git a/layout/generic/nsTextFrame.cpp b/layout/generic/nsTextFrame.cpp
index 9260b28da96..3aadca178b2 100644
--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@@ -331,7 +331,8 @@ public:
   {
     // Set the frame state bit for text frames to mark them as replaced.
     // XXX kipp: temporary
-    return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eReplaced));
+    return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eReplaced |
+                                             nsIFrame::eLineParticipant));
   }
   
 #ifdef DEBUG
diff --git a/layout/generic/nsTextFrameThebes.cpp b/layout/generic/nsTextFrameThebes.cpp
index b30d347e3d8..ddb991cd3d6 100644
--- a/layout/generic/nsTextFrameThebes.cpp
+++ b/layout/generic/nsTextFrameThebes.cpp
@@ -374,7 +374,8 @@ public:
   {
     // Set the frame state bit for text frames to mark them as replaced.
     // XXX kipp: temporary
-    return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eReplaced));
+    return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eReplaced |
+                                             nsIFrame::eLineParticipant));
   }
 
 #ifdef DEBUG