diff --git a/mozilla/layout/generic/nsFirstLetterFrame.cpp b/mozilla/layout/generic/nsFirstLetterFrame.cpp
index 7d41c7e62b8..6d12d5737a1 100644
--- a/mozilla/layout/generic/nsFirstLetterFrame.cpp
+++ b/mozilla/layout/generic/nsFirstLetterFrame.cpp
@@ -224,23 +224,25 @@ nsFirstLetterFrame::Reflow(nsPresContext*          aPresContext,
     ll.BeginLineReflow(bp.left, bp.top, availSize.width, NS_UNCONSTRAINEDSIZE,
                        PR_FALSE, PR_TRUE);
     rs.mLineLayout = ≪
+    ll.SetInFirstLetter(PR_TRUE);
     ll.SetFirstLetterStyleOK(PR_TRUE);
 
     kid->WillReflow(aPresContext);
     kid->Reflow(aPresContext, aMetrics, rs, aReflowStatus);
 
     ll.EndLineReflow();
+    ll.SetInFirstLetter(PR_FALSE);
   }
   else {
     // Pretend we are a span and reflow the child frame
     nsLineLayout* ll = aReflowState.mLineLayout;
     PRBool        pushedFrame;
 
-    NS_ASSERTION(ll->GetFirstLetterStyleOK() || GetPrevInFlow(),
-                 "First-in-flow first-letter should have first-letter style enabled in nsLineLayout!");
+    ll->SetInFirstLetter(GetPrevContinuation() == nsnull);
     ll->BeginSpan(this, &aReflowState, bp.left, availSize.width);
     ll->ReflowFrame(kid, aReflowStatus, &aMetrics, pushedFrame);
     ll->EndSpan(this);
+    ll->SetInFirstLetter(PR_FALSE);
   }
 
   // Place and size the child and update the output metrics
diff --git a/mozilla/layout/generic/nsLineLayout.h b/mozilla/layout/generic/nsLineLayout.h
index ae3c470faf0..c6182f0c56e 100644
--- a/mozilla/layout/generic/nsLineLayout.h
+++ b/mozilla/layout/generic/nsLineLayout.h
@@ -153,7 +153,8 @@ protected:
 #define LL_NEEDBACKUP                  0x00000400
 #define LL_INFIRSTLINE                 0x00000800
 #define LL_GOTLINEBOX                  0x00001000
-#define LL_LASTFLAG                    LL_GOTLINEBOX
+#define LL_INFIRSTLETTER               0x00002000
+#define LL_LASTFLAG                    LL_INFIRSTLETTER
 
   PRUint16 mFlags;
 
@@ -223,6 +224,14 @@ public:
     SetFlag(LL_FIRSTLETTERSTYLEOK, aSetting);
   }
 
+  PRBool GetInFirstLetter() const {
+    return GetFlag(LL_INFIRSTLETTER);
+  }
+
+  void SetInFirstLetter(PRBool aSetting) {
+    SetFlag(LL_INFIRSTLETTER, aSetting);
+  }
+
   PRBool GetInFirstLine() const {
     return GetFlag(LL_INFIRSTLINE);
   }
diff --git a/mozilla/layout/generic/nsTextFrameThebes.cpp b/mozilla/layout/generic/nsTextFrameThebes.cpp
index 56e34aa3bf6..e39fea52ca6 100644
--- a/mozilla/layout/generic/nsTextFrameThebes.cpp
+++ b/mozilla/layout/generic/nsTextFrameThebes.cpp
@@ -5518,10 +5518,10 @@ nsTextFrame::Reflow(nsPresContext*           aPresContext,
   PRBool completedFirstLetter = PR_FALSE;
   // Layout dependent styles are a problem because we need to reconstruct
   // the gfxTextRun based on our layout.
-  if (lineLayout.GetFirstLetterStyleOK() || lineLayout.GetInFirstLine()) {
+  if (lineLayout.GetInFirstLetter() || lineLayout.GetInFirstLine()) {
     SetLength(maxContentLength);
 
-    if (lineLayout.GetFirstLetterStyleOK()) {
+    if (lineLayout.GetInFirstLetter()) {
       // floating first-letter boundaries are significant in textrun
       // construction, so clear the textrun out every time we hit a first-letter
       // and have changed our length (which controls the first-letter boundary)
@@ -5531,7 +5531,18 @@ nsTextFrame::Reflow(nsPresContext*           aPresContext,
         EnsureTextRun(ctx, lineContainer, lineLayout.GetLine(), &flowEndInTextRun);
 
       if (mTextRun) {
-        completedFirstLetter = FindFirstLetterRange(frag, mTextRun, offset, iter, &length);
+        if (lineLayout.GetFirstLetterStyleOK()) {
+          completedFirstLetter =
+            FindFirstLetterRange(frag, mTextRun, offset, iter, &length);
+        } else {
+          // We're in a first-letter frame's first in flow, so if there
+          // was a first-letter, we'd be it. However, for one reason
+          // or another (e.g., preformatted line break before this text),
+          // we're not actually supposed to have first-letter style. So
+          // just make a zero-length first-letter.
+          length = 0;
+          completedFirstLetter = PR_TRUE;
+        }
         if (length) {
           AddStateBits(TEXT_FIRST_LETTER);
         }
@@ -5797,9 +5808,6 @@ nsTextFrame::Reflow(nsPresContext*           aPresContext,
       lineLayout.NotifyOptionalBreakPosition(mContent, offset + length, PR_TRUE);
     }
   }
-  if (completedFirstLetter) {
-    lineLayout.SetFirstLetterStyleOK(PR_FALSE);
-  }
 
   // Compute reflow status
   aStatus = contentLength == maxContentLength
diff --git a/mozilla/layout/reftests/first-letter/429968-1-ref.html b/mozilla/layout/reftests/first-letter/429968-1-ref.html
new file mode 100644
index 00000000000..be914274734
--- /dev/null
+++ b/mozilla/layout/reftests/first-letter/429968-1-ref.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+</style>
+</head>
+<body>
+AB</body>
+</html>
diff --git a/mozilla/layout/reftests/first-letter/429968-1a.html b/mozilla/layout/reftests/first-letter/429968-1a.html
new file mode 100644
index 00000000000..db0013832b5
--- /dev/null
+++ b/mozilla/layout/reftests/first-letter/429968-1a.html
@@ -0,0 +1,11 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+#inner::first-letter { color:red; text-decoration:underline; font-size:200%; }
+</style>
+</head>
+<body><div id="inner"><span>
+</span>AB</div></body>
+</html>
diff --git a/mozilla/layout/reftests/first-letter/429968-1b.html b/mozilla/layout/reftests/first-letter/429968-1b.html
new file mode 100644
index 00000000000..72dd1095a3b
--- /dev/null
+++ b/mozilla/layout/reftests/first-letter/429968-1b.html
@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:blue; }
+#inner::first-letter { color:red; text-decoration:underline; font-size:200%; }
+</style>
+</head>
+<body><div id="inner"><span>
+</span>AB</div></body>
+<script>
+document.body.offsetTop;
+document.body.style.color = "black";
+</script>
+</html>
diff --git a/mozilla/layout/reftests/first-letter/429968-2-ref.html b/mozilla/layout/reftests/first-letter/429968-2-ref.html
new file mode 100644
index 00000000000..b541822a4d5
--- /dev/null
+++ b/mozilla/layout/reftests/first-letter/429968-2-ref.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+body { color:black; }
+span { color:lime; }
+</style>
+</head>
+<body><span>A</span>B</body>
+</html>
diff --git a/mozilla/layout/reftests/first-letter/429968-2a.html b/mozilla/layout/reftests/first-letter/429968-2a.html
new file mode 100644
index 00000000000..dd7d4091c34
--- /dev/null
+++ b/mozilla/layout/reftests/first-letter/429968-2a.html
@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+#inner::first-letter { color:lime; }
+</style>
+</head>
+<body><div id="inner"><span id="s">
+</span>AB</div></body>
+<script>
+document.body.offsetTop;
+document.getElementById("s").textContent = "";
+</script>
+</html>
diff --git a/mozilla/layout/reftests/first-letter/429968-2b.html b/mozilla/layout/reftests/first-letter/429968-2b.html
new file mode 100644
index 00000000000..4f3daffa101
--- /dev/null
+++ b/mozilla/layout/reftests/first-letter/429968-2b.html
@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+#inner::first-letter { color:lime; }
+</style>
+</head>
+<body><div id="inner"><span id="s">
+</span>AB</div></body>
+<script>
+document.body.offsetTop;
+document.getElementById("s").firstChild.data = "";
+</script>
+</html>
diff --git a/mozilla/layout/reftests/first-letter/429968-2c.html b/mozilla/layout/reftests/first-letter/429968-2c.html
new file mode 100644
index 00000000000..65bb91d3db6
--- /dev/null
+++ b/mozilla/layout/reftests/first-letter/429968-2c.html
@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+#inner::first-letter { color:lime; }
+</style>
+</head>
+<body><div id="inner"><span id="s">
+</span>AB</div></body>
+<script>
+document.body.offsetTop;
+document.getElementById("s").style.whiteSpace = "normal";
+</script>
+</html>
diff --git a/mozilla/layout/reftests/first-letter/reftest.list b/mozilla/layout/reftests/first-letter/reftest.list
index 34a8442bfb5..2cca7b71e62 100644
--- a/mozilla/layout/reftests/first-letter/reftest.list
+++ b/mozilla/layout/reftests/first-letter/reftest.list
@@ -31,3 +31,8 @@ random == dynamic-3b.html dynamic-3-ref.html
 random-if(MOZ_WIDGET_TOOLKIT=="gtk2") == 329069-1.html 329069-1-ref.html # failure is font-dependent, may be related to bug 404848
 == 342120-1.xhtml 342120-1-ref.xhtml
 == 379799-1.html 379799-1-ref.html
+== 429968-1a.html 429968-1-ref.html
+== 429968-1b.html 429968-1-ref.html
+== 429968-2a.html 429968-2-ref.html
+== 429968-2b.html 429968-2-ref.html
+== 429968-2c.html 429968-2-ref.html