diff --git a/mozilla/layout/mathml/base/src/nsMathMLChar.cpp b/mozilla/layout/mathml/base/src/nsMathMLChar.cpp
index a1f64d2192e..d60a0c95819 100644
--- a/mozilla/layout/mathml/base/src/nsMathMLChar.cpp
+++ b/mozilla/layout/mathml/base/src/nsMathMLChar.cpp
@@ -1213,22 +1213,24 @@ nsMathMLChar::SetData(nsIPresContext* aPresContext,
   mData = aData;
   // some assumptions until proven otherwise
   // note that mGlyph is not initialized
+  mOperator = -1;
   mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED;
   mBoundingMetrics.Clear();
   mGlyphTable = nsnull;
   // check if stretching is applicable ...
   if (gGlyphTableList && (1 == mData.Length())) {
-    PRInt32 k = nsMathMLOperators::FindStretchyOperator(mData[0]);
-    if (k != kNotFound) {
-      mDirection = nsMathMLOperators::GetStretchyDirectionAt(k);
+    mOperator = nsMathMLOperators::FindStretchyOperator(mData[0]);
+    if (mOperator >= 0) {
+      mDirection = nsMathMLOperators::GetStretchyDirectionAt(mOperator);
       // default tentative table (not the one that is necessarily going to be used)
       mGlyphTable = gGlyphTableList->GetGlyphTableFor(aPresContext, this);
       // commom case: we won't bother with the stretching if there is
       // no glyph table for us...
       if (!mGlyphTable) {
+        mOperator = -1;
         mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED;
         // never try to stretch this operator again
-        nsMathMLOperators::DisableStretchyOperatorAt(k);
+        nsMathMLOperators::DisableStretchyOperatorAt(mOperator);
       }
     }
   }
@@ -1422,6 +1424,14 @@ nsMathMLChar::Stretch(nsIPresContext*      aPresContext,
   nsresult rv = NS_OK;
   nsStretchDirection direction = aStretchDirection;
 
+  // if we have been called before, and we didn't actually stretch, our
+  // direction may have been set to NS_STRETCH_DIRECTION_UNSUPPORTED.
+  // So first set our direction back to its instrinsic value
+  if (mOperator >= 0) {
+    // mOperator is initialized in SetData() and remains unchanged
+    mDirection = nsMathMLOperators::GetStretchyDirectionAt(mOperator);
+  }
+
   // if no specified direction, attempt to stretch in our preferred direction
   if (direction == NS_STRETCH_DIRECTION_DEFAULT) {
     direction = mDirection;
@@ -1448,7 +1458,7 @@ nsMathMLChar::Stretch(nsIPresContext*      aPresContext,
   if (NS_FAILED(rv)) {
     NS_WARNING("GetBoundingMetrics failed");
     // ensure that the char later behaves like a normal char
-    // XXX to reset in dynamic updates @ ContentChanged()
+    // (will be reset back to its intrinsic value in case of dynamic updates)
     mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED;
     return rv;
   }
@@ -1459,7 +1469,8 @@ nsMathMLChar::Stretch(nsIPresContext*      aPresContext,
   // quick return if there is nothing special about this char
   if (!mGlyphTable || (mDirection != direction)) {
     // ensure that the char later behaves like a normal char
-    mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED; // XXX to reset in dynamic updates
+    // (will be reset back to its intrinsic value in case of dynamic updates)
+    mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED;
     return NS_OK;
   }
 
@@ -1484,7 +1495,8 @@ nsMathMLChar::Stretch(nsIPresContext*      aPresContext,
   // if we are not a largeop in display mode, return if size fits
   if (!largeop && IsSizeOK(charSize, targetSize, aStretchHint)) {
     // ensure that the char later behaves like a normal char
-    mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED; // XXX to reset in dynamic updates
+    // (will be reset back to its intrinsic value in case of dynamic updates)
+    mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED;
     return NS_OK;
   }
 
@@ -1725,7 +1737,8 @@ nsMathMLChar::Stretch(nsIPresContext*      aPresContext,
 done:
   if (bestGlyph == startingGlyph) { // nothing happened
     // ensure that the char behaves like a normal char
-    mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED; // XXX to reset in dynamic updates
+    // (will be reset back to its intrinsic value in case of dynamic updates)
+    mDirection = NS_STRETCH_DIRECTION_UNSUPPORTED;
   }
   else {
     // will stretch
diff --git a/mozilla/layout/mathml/base/src/nsMathMLChar.h b/mozilla/layout/mathml/base/src/nsMathMLChar.h
index 2fd005729f3..e20b9ae65e7 100644
--- a/mozilla/layout/mathml/base/src/nsMathMLChar.h
+++ b/mozilla/layout/mathml/base/src/nsMathMLChar.h
@@ -171,6 +171,7 @@ protected:
 
 private:
   nsRect             mRect;
+  PRInt32            mOperator;
   nsStretchDirection mDirection;
   nsBoundingMetrics  mBoundingMetrics;
   nsIStyleContext*   mStyleContext;
diff --git a/mozilla/layout/mathml/base/src/nsMathMLmfencedFrame.cpp b/mozilla/layout/mathml/base/src/nsMathMLmfencedFrame.cpp
index e35df28f416..a7d755b8f05 100644
--- a/mozilla/layout/mathml/base/src/nsMathMLmfencedFrame.cpp
+++ b/mozilla/layout/mathml/base/src/nsMathMLmfencedFrame.cpp
@@ -479,7 +479,6 @@ nsMathMLmfencedFrame::ReflowChar(nsIPresContext*      aPresContext,
  
     nsAutoString data;
     aMathMLChar->GetData(data);
-    aMathMLChar->SetData(aPresContext, data); // XXX hack to reset, bug 45010
     PRBool found = nsMathMLOperators::LookupOperator(data, aForm,              
                                            &flags, &leftSpace, &rightSpace);
 
diff --git a/mozilla/layout/mathml/base/src/nsMathMLmoFrame.cpp b/mozilla/layout/mathml/base/src/nsMathMLmoFrame.cpp
index 954ed3f3e24..c8e6a2af258 100644
--- a/mozilla/layout/mathml/base/src/nsMathMLmoFrame.cpp
+++ b/mozilla/layout/mathml/base/src/nsMathMLmoFrame.cpp
@@ -109,8 +109,6 @@ void
 nsMathMLmoFrame::ProcessTextData(nsIPresContext* aPresContext)
 {
   mFlags = 0;
-  if (!mFrames.FirstChild())
-    return;
 
   // kids can be comment-nodes, attribute-nodes, text-nodes...
   // we use the DOM to ensure that we only look at text-nodes...
@@ -303,7 +301,6 @@ nsMathMLmoFrame::ProcessOperatorData(nsIPresContext* aPresContext)
     float rspace = 0.0f;
     nsAutoString data;
     mMathMLChar.GetData(data);
-    mMathMLChar.SetData(aPresContext, data); // XXX hack to reset, bug 45010
     PRBool found = nsMathMLOperators::LookupOperator(data, form, &mFlags, &lspace, &rspace);
     if (found) {
       // cache the default values of lspace & rspace that we get from the dictionary.
diff --git a/mozilla/layout/mathml/base/src/nsMathMLmsqrtFrame.cpp b/mozilla/layout/mathml/base/src/nsMathMLmsqrtFrame.cpp
index fc1e604e911..8ffb086bc43 100644
--- a/mozilla/layout/mathml/base/src/nsMathMLmsqrtFrame.cpp
+++ b/mozilla/layout/mathml/base/src/nsMathMLmsqrtFrame.cpp
@@ -228,8 +228,6 @@ nsMathMLmsqrtFrame::Reflow(nsIPresContext*          aPresContext,
 
   // height(radical) should be >= height(base) + psi + ruleThickness
   nsBoundingMetrics radicalSize;
-  nsAutoString sqrChar; sqrChar.Assign(kSqrChar);
-  mSqrChar.SetData(aPresContext, sqrChar); // XXX hack to reset the char, bug 45010
   mSqrChar.Stretch(aPresContext, renderingContext,
                    NS_STRETCH_DIRECTION_VERTICAL, 
                    contSize, radicalSize,