diff --git a/mozilla/layout/base/public/nsIFrame.h b/mozilla/layout/base/public/nsIFrame.h
index 6bab9b8e0a0..133c08b7c4c 100644
--- a/mozilla/layout/base/public/nsIFrame.h
+++ b/mozilla/layout/base/public/nsIFrame.h
@@ -130,6 +130,9 @@ typedef PRUint32 nsFrameState;
 // If this bit is set, then the frame reflects content that may be selected
 #define NS_FRAME_SELECTED_CONTENT 0x00000200
 
+// If this bit is set, then the frame is dirty and needs to be reflowed
+#define NS_FRAME_IS_DIRTY 0x00000400
+
 // The low 16 bits of the frame state word are reserved by this API.
 #define NS_FRAME_RESERVED 0x0000FFFF
 
diff --git a/mozilla/layout/generic/nsFrame.cpp b/mozilla/layout/generic/nsFrame.cpp
index 55c1fea4bbb..bd5191a8aeb 100644
--- a/mozilla/layout/generic/nsFrame.cpp
+++ b/mozilla/layout/generic/nsFrame.cpp
@@ -1037,7 +1037,7 @@ nsFrame::DidReflow(nsIPresContext& aPresContext,
   NS_FRAME_TRACE_MSG(NS_FRAME_TRACE_CALLS,
                      ("nsFrame::DidReflow: aStatus=%d", aStatus));
   if (NS_FRAME_REFLOW_FINISHED == aStatus) {
-    mState &= ~(NS_FRAME_IN_REFLOW | NS_FRAME_FIRST_REFLOW);
+    mState &= ~(NS_FRAME_IN_REFLOW | NS_FRAME_FIRST_REFLOW | NS_FRAME_IS_DIRTY);
 
     // Size and position the view if requested
     if ((nsnull != mView) && (NS_FRAME_SYNC_FRAME_AND_VIEW & mState)) {
diff --git a/mozilla/layout/generic/nsIFrame.h b/mozilla/layout/generic/nsIFrame.h
index 6bab9b8e0a0..133c08b7c4c 100644
--- a/mozilla/layout/generic/nsIFrame.h
+++ b/mozilla/layout/generic/nsIFrame.h
@@ -130,6 +130,9 @@ typedef PRUint32 nsFrameState;
 // If this bit is set, then the frame reflects content that may be selected
 #define NS_FRAME_SELECTED_CONTENT 0x00000200
 
+// If this bit is set, then the frame is dirty and needs to be reflowed
+#define NS_FRAME_IS_DIRTY 0x00000400
+
 // The low 16 bits of the frame state word are reserved by this API.
 #define NS_FRAME_RESERVED 0x0000FFFF
 
diff --git a/mozilla/layout/html/base/src/nsFrame.cpp b/mozilla/layout/html/base/src/nsFrame.cpp
index 55c1fea4bbb..bd5191a8aeb 100644
--- a/mozilla/layout/html/base/src/nsFrame.cpp
+++ b/mozilla/layout/html/base/src/nsFrame.cpp
@@ -1037,7 +1037,7 @@ nsFrame::DidReflow(nsIPresContext& aPresContext,
   NS_FRAME_TRACE_MSG(NS_FRAME_TRACE_CALLS,
                      ("nsFrame::DidReflow: aStatus=%d", aStatus));
   if (NS_FRAME_REFLOW_FINISHED == aStatus) {
-    mState &= ~(NS_FRAME_IN_REFLOW | NS_FRAME_FIRST_REFLOW);
+    mState &= ~(NS_FRAME_IN_REFLOW | NS_FRAME_FIRST_REFLOW | NS_FRAME_IS_DIRTY);
 
     // Size and position the view if requested
     if ((nsnull != mView) && (NS_FRAME_SYNC_FRAME_AND_VIEW & mState)) {