diff --git a/mozilla/layout/html/table/src/nsTableFrame.cpp b/mozilla/layout/html/table/src/nsTableFrame.cpp
index 3c14a479f3b..bc1202e3d86 100644
--- a/mozilla/layout/html/table/src/nsTableFrame.cpp
+++ b/mozilla/layout/html/table/src/nsTableFrame.cpp
@@ -1575,7 +1575,7 @@ NS_METHOD nsTableFrame::Reflow(nsIPresContext& aPresContext,
     if (PR_FALSE==IsFirstPassValid())
     {
       if (PR_TRUE==gsDebug || PR_TRUE==gsDebugIR) printf("TIF Reflow: first pass is invalid\n");
-      rv = ResizeReflowPass1(aPresContext, aDesiredSize, aReflowState, aStatus);
+      rv = ResizeReflowPass1(aPresContext, aDesiredSize, aReflowState, aStatus, nsnull, aReflowState.reason);
       if (NS_FAILED(rv))
         return rv;
       needsRecalc=PR_TRUE;
@@ -1641,10 +1641,12 @@ NS_METHOD nsTableFrame::Reflow(nsIPresContext& aPresContext,
   * NOTE: should never get called on a continuing frame!  All cached pass1 state
   *       is stored in the inner table first-in-flow.
   */
-NS_METHOD nsTableFrame::ResizeReflowPass1(nsIPresContext& aPresContext,
-                                               nsHTMLReflowMetrics& aDesiredSize,
-                                               const nsHTMLReflowState& aReflowState,
-                                               nsReflowStatus& aStatus)
+NS_METHOD nsTableFrame::ResizeReflowPass1(nsIPresContext&          aPresContext,
+                                          nsHTMLReflowMetrics&     aDesiredSize,
+                                          const nsHTMLReflowState& aReflowState,
+                                          nsReflowStatus&          aStatus,
+                                          nsTableRowGroupFrame *   aStartingFrame,
+                                          nsReflowReason           aReason)
 {
   NS_PRECONDITION(aReflowState.frame == this, "bad reflow state");
   NS_PRECONDITION(aReflowState.parentReflowState->frame == mGeometricParent,
@@ -1680,13 +1682,15 @@ NS_METHOD nsTableFrame::ResizeReflowPass1(nsIPresContext& aPresContext,
   nscoord rightInset = borderPadding.right;
   nscoord bottomInset = borderPadding.bottom;
   nscoord leftInset = borderPadding.left;
-  nsReflowReason  reflowReason = aReflowState.reason;
 
   nsStyleTable* tableStyle;
   GetStyleData(eStyleStruct_Table, (nsStyleStruct *&)tableStyle);
   if (NS_STYLE_TABLE_LAYOUT_FIXED!=tableStyle->mLayoutStrategy)
   {
-    for (nsIFrame* kidFrame = mFirstChild; nsnull != kidFrame; kidFrame->GetNextSibling(kidFrame)) 
+    nsIFrame* kidFrame = aStartingFrame;
+    if (nsnull==kidFrame)
+      kidFrame=mFirstChild;
+    for ( ; nsnull != kidFrame; kidFrame->GetNextSibling(kidFrame)) 
     {
       const nsStyleDisplay *childDisplay;
       kidFrame->GetStyleData(eStyleStruct_Display, ((nsStyleStruct *&)childDisplay));
@@ -1699,8 +1703,7 @@ NS_METHOD nsTableFrame::ResizeReflowPass1(nsIPresContext& aPresContext,
       }
       nsSize maxKidElementSize(0,0);
       nsHTMLReflowState kidReflowState(aPresContext, kidFrame, aReflowState,
-                                       availSize);
-
+                                       availSize, aReason);
       PRInt32 yCoord = y;
       if (NS_UNCONSTRAINEDSIZE!=yCoord)
         yCoord+= topInset;
@@ -2166,7 +2169,8 @@ NS_METHOD nsTableFrame::IR_RowGroupInserted(nsIPresContext&        aPresContext,
                                             nsTableRowGroupFrame * aInsertedFrame,
                                             PRBool                 aReplace)
 {
-  nsresult rv;
+  nsresult rv = IR_UnknownFrameInserted(aPresContext, aDesiredSize, aReflowState,
+                                        aStatus, (nsIFrame*)aInsertedFrame, aReplace);
   // inserting the rowgroup only effects reflow if the rowgroup includes at least one row
   return rv;
 }
@@ -2179,26 +2183,22 @@ NS_METHOD nsTableFrame::IR_RowGroupAppended(nsIPresContext&        aPresContext,
                                             nsTableRowGroupFrame * aAppendedFrame)
 {
   // hook aAppendedFrame into the child list
-  nsIFrame *lastChild = mFirstChild;
-  nsIFrame *nextChild = lastChild;
-  while (nsnull!=nextChild)
-  {
-    lastChild = nextChild;
-    nextChild->GetNextSibling(nextChild);
-  }
-  if (nsnull==lastChild)
-    mFirstChild = aAppendedFrame;
-  else
-    lastChild->SetNextSibling(aAppendedFrame);
+  nsresult rv = IR_UnknownFrameInserted(aPresContext, aDesiredSize, aReflowState,
+                                        aStatus, (nsIFrame*)aAppendedFrame, PR_FALSE);
+  if (NS_FAILED(rv))
+    return rv;
 
   // account for the cells in the rows that are children of aAppendedFrame
-  nsresult rv = DidAppendRowGroup((nsTableRowGroupFrame*)aAppendedFrame);
+  rv = DidAppendRowGroup((nsTableRowGroupFrame*)aAppendedFrame);
 
   // do a pass-1 layout of all the cells in all the rows of the rowgroup
-  InvalidateFirstPassCache();
+  rv = ResizeReflowPass1(aPresContext, aDesiredSize, aReflowState.reflowState, aStatus, 
+                         aAppendedFrame, eReflowReason_Initial);
+  if (NS_FAILED(rv))
+    return rv;
 
-  // if any column widths have to change due to this, re-init the layout strategy
-  // mTableLayoutStrategy->Initialize(aDesiredSize.aMaxElementSize);  //XXX for now, we're just doing the whole enchelada
+  // if any column widths have to change due to this, rebalance column widths
+  mTableLayoutStrategy->Initialize(aDesiredSize.maxElementSize);  
 
   return rv;
 }
diff --git a/mozilla/layout/html/table/src/nsTableFrame.h b/mozilla/layout/html/table/src/nsTableFrame.h
index 05aacc6df15..021aca9fc3a 100644
--- a/mozilla/layout/html/table/src/nsTableFrame.h
+++ b/mozilla/layout/html/table/src/nsTableFrame.h
@@ -22,6 +22,8 @@
 #include "nsContainerFrame.h"
 #include "nsStyleCoord.h"
 #include "nsStyleConsts.h"
+#include "nsIFrameReflow.h"   // for nsReflowReason enum
+
 
 class nsCellMap;
 class nsVoidArray;
@@ -269,13 +271,17 @@ protected:
     * Pass 1 only needs to be executed once no matter how many times the table is resized, 
     * as long as content and style don't change.  This is managed in the member variable mFirstPassIsValid.
     * The layout information for each cell is cached in mColumLayoutData.
+    * Incremental layout can take advantage of aStartingFrame to pick up where a previous
+    * ResizeReflowPass1 left off.
     *
     * @see Reflow
     */
   NS_IMETHOD ResizeReflowPass1(nsIPresContext&          aPresContext,
                                nsHTMLReflowMetrics&     aDesiredSize,
                                const nsHTMLReflowState& aReflowState,
-                               nsReflowStatus&          aStatus);
+                               nsReflowStatus&          aStatus,
+                               nsTableRowGroupFrame *   aStartingFrame,
+                               nsReflowReason           aReason);
 
   /** second pass of ResizeReflow.
     * lays out all table content with aMaxSize(computed_table_width, given_table_height) 
@@ -298,10 +304,10 @@ protected:
     *
     * @see Reflow
     */
-  NS_IMETHOD IncrementalReflow(nsIPresContext&      aPresContext,
-                               nsHTMLReflowMetrics& aDesiredSize,
+  NS_IMETHOD IncrementalReflow(nsIPresContext&          aPresContext,
+                               nsHTMLReflowMetrics&     aDesiredSize,
                                const nsHTMLReflowState& aReflowState,
-                               nsReflowStatus&      aStatus);
+                               nsReflowStatus&          aStatus);
 
   NS_IMETHOD IR_TargetIsChild(nsIPresContext&        aPresContext,
                               nsHTMLReflowMetrics&   aDesiredSize,
diff --git a/mozilla/layout/html/table/src/nsTableRowGroupFrame.cpp b/mozilla/layout/html/table/src/nsTableRowGroupFrame.cpp
index 09df6333da1..8ffa859632a 100644
--- a/mozilla/layout/html/table/src/nsTableRowGroupFrame.cpp
+++ b/mozilla/layout/html/table/src/nsTableRowGroupFrame.cpp
@@ -606,8 +606,11 @@ void nsTableRowGroupFrame::ShrinkWrapChildren(nsIPresContext* aPresContext,
         cellFrame->GetStyleData(eStyleStruct_Display, ((nsStyleStruct *&)childDisplay));
         if (NS_STYLE_DISPLAY_TABLE_CELL == childDisplay->mDisplay)
         {
-          PRInt32 rowSpan = ((nsTableFrame*)mGeometricParent)->
-                                GetEffectiveRowSpan(rowIndex,(nsTableCellFrame*)cellFrame);
+          nsTableFrame *tableFrame=nsnull;
+          nsresult rv = nsTableFrame::GetTableFrame(this, tableFrame);
+          if (NS_FAILED(rv) || nsnull==tableFrame)
+            return;
+          PRInt32 rowSpan = tableFrame->GetEffectiveRowSpan(rowIndex,(nsTableCellFrame*)cellFrame);
           if (rowSpan > 1)
           { // found a cell with rowspan > 1, determine its height
             nscoord heightOfRowsSpanned = 0;
diff --git a/mozilla/layout/html/tests/TableIncrementalReflow.html b/mozilla/layout/html/tests/TableIncrementalReflow.html
index e363cda487b..a09d34b7694 100644
--- a/mozilla/layout/html/tests/TableIncrementalReflow.html
+++ b/mozilla/layout/html/tests/TableIncrementalReflow.html
@@ -67,10 +67,33 @@ function deleteCol() {
   table.removeChild(col);
 }
 
+
 function insertRowGroup() {
+  var table = document.getElementsByTagName("TABLE")[0];
+  var refRowGroup = document.getElementsByTagName("TBODY")[0];
+  var rowGroup = document.createElement("TBODY", null);
+  table.insertBefore(rowGroup, refRowGroup);
+  dump("inserted empty ROWGROUP as first rowgroup in table");
+}
+
+function appendRowGroup() {
   var table = document.getElementsByTagName("TABLE")[0];
   var rowGroup = document.createElement("TBODY", null);
   table.appendChild(rowGroup);
+  dump("appended empty ROWGROUP");
+}
+
+function appendRowGroupWithContent() {
+  var table = document.getElementsByTagName("TABLE")[0];
+  var rowGroup = document.createElement("TBODY", null);
+  var row = document.createElement("TR", null);
+  var cell = document.createElement("TD", null);
+  var text = document.createTextNode("here is content in the cell from the script");
+  cell.appendChild(text);
+  row.appendChild(cell);
+  rowGroup.appendChild(row);  
+  table.appendChild(rowGroup);
+  dump("appended ROWGROUP with 1 row and 1 cell");
 }
 
 function deleteRowGroup() {
@@ -122,6 +145,7 @@ all delete buttons currently remove the first item of <type> found
 <INPUT TYPE="button" NAME="Ins RowGroup" VALUE="InsertRG" onClick="insertRowGroup()" width=100>
 <INPUT TYPE="button" NAME="App RowGroup" VALUE="AppendRG" onClick="appendRowGroup()" width=100>
 <INPUT TYPE="button" NAME="Del RowGroup" VALUE="DeleteRG" onClick="deleteRowGroup()" width=100>
+<INPUT TYPE="button" NAME="App RowGroup with content" VALUE="AppendRG with content" onClick="appendRowGroupWithContent()" width=100>
 <br>
 <INPUT TYPE="button" NAME="Ins Row" VALUE="InsertRow" onClick="insertRow()" width=100>
 <INPUT TYPE="button" NAME="App Row" VALUE="AppendRow" onClick="appendRow()" width=100>
diff --git a/mozilla/layout/tables/nsTableFrame.cpp b/mozilla/layout/tables/nsTableFrame.cpp
index 3c14a479f3b..bc1202e3d86 100644
--- a/mozilla/layout/tables/nsTableFrame.cpp
+++ b/mozilla/layout/tables/nsTableFrame.cpp
@@ -1575,7 +1575,7 @@ NS_METHOD nsTableFrame::Reflow(nsIPresContext& aPresContext,
     if (PR_FALSE==IsFirstPassValid())
     {
       if (PR_TRUE==gsDebug || PR_TRUE==gsDebugIR) printf("TIF Reflow: first pass is invalid\n");
-      rv = ResizeReflowPass1(aPresContext, aDesiredSize, aReflowState, aStatus);
+      rv = ResizeReflowPass1(aPresContext, aDesiredSize, aReflowState, aStatus, nsnull, aReflowState.reason);
       if (NS_FAILED(rv))
         return rv;
       needsRecalc=PR_TRUE;
@@ -1641,10 +1641,12 @@ NS_METHOD nsTableFrame::Reflow(nsIPresContext& aPresContext,
   * NOTE: should never get called on a continuing frame!  All cached pass1 state
   *       is stored in the inner table first-in-flow.
   */
-NS_METHOD nsTableFrame::ResizeReflowPass1(nsIPresContext& aPresContext,
-                                               nsHTMLReflowMetrics& aDesiredSize,
-                                               const nsHTMLReflowState& aReflowState,
-                                               nsReflowStatus& aStatus)
+NS_METHOD nsTableFrame::ResizeReflowPass1(nsIPresContext&          aPresContext,
+                                          nsHTMLReflowMetrics&     aDesiredSize,
+                                          const nsHTMLReflowState& aReflowState,
+                                          nsReflowStatus&          aStatus,
+                                          nsTableRowGroupFrame *   aStartingFrame,
+                                          nsReflowReason           aReason)
 {
   NS_PRECONDITION(aReflowState.frame == this, "bad reflow state");
   NS_PRECONDITION(aReflowState.parentReflowState->frame == mGeometricParent,
@@ -1680,13 +1682,15 @@ NS_METHOD nsTableFrame::ResizeReflowPass1(nsIPresContext& aPresContext,
   nscoord rightInset = borderPadding.right;
   nscoord bottomInset = borderPadding.bottom;
   nscoord leftInset = borderPadding.left;
-  nsReflowReason  reflowReason = aReflowState.reason;
 
   nsStyleTable* tableStyle;
   GetStyleData(eStyleStruct_Table, (nsStyleStruct *&)tableStyle);
   if (NS_STYLE_TABLE_LAYOUT_FIXED!=tableStyle->mLayoutStrategy)
   {
-    for (nsIFrame* kidFrame = mFirstChild; nsnull != kidFrame; kidFrame->GetNextSibling(kidFrame)) 
+    nsIFrame* kidFrame = aStartingFrame;
+    if (nsnull==kidFrame)
+      kidFrame=mFirstChild;
+    for ( ; nsnull != kidFrame; kidFrame->GetNextSibling(kidFrame)) 
     {
       const nsStyleDisplay *childDisplay;
       kidFrame->GetStyleData(eStyleStruct_Display, ((nsStyleStruct *&)childDisplay));
@@ -1699,8 +1703,7 @@ NS_METHOD nsTableFrame::ResizeReflowPass1(nsIPresContext& aPresContext,
       }
       nsSize maxKidElementSize(0,0);
       nsHTMLReflowState kidReflowState(aPresContext, kidFrame, aReflowState,
-                                       availSize);
-
+                                       availSize, aReason);
       PRInt32 yCoord = y;
       if (NS_UNCONSTRAINEDSIZE!=yCoord)
         yCoord+= topInset;
@@ -2166,7 +2169,8 @@ NS_METHOD nsTableFrame::IR_RowGroupInserted(nsIPresContext&        aPresContext,
                                             nsTableRowGroupFrame * aInsertedFrame,
                                             PRBool                 aReplace)
 {
-  nsresult rv;
+  nsresult rv = IR_UnknownFrameInserted(aPresContext, aDesiredSize, aReflowState,
+                                        aStatus, (nsIFrame*)aInsertedFrame, aReplace);
   // inserting the rowgroup only effects reflow if the rowgroup includes at least one row
   return rv;
 }
@@ -2179,26 +2183,22 @@ NS_METHOD nsTableFrame::IR_RowGroupAppended(nsIPresContext&        aPresContext,
                                             nsTableRowGroupFrame * aAppendedFrame)
 {
   // hook aAppendedFrame into the child list
-  nsIFrame *lastChild = mFirstChild;
-  nsIFrame *nextChild = lastChild;
-  while (nsnull!=nextChild)
-  {
-    lastChild = nextChild;
-    nextChild->GetNextSibling(nextChild);
-  }
-  if (nsnull==lastChild)
-    mFirstChild = aAppendedFrame;
-  else
-    lastChild->SetNextSibling(aAppendedFrame);
+  nsresult rv = IR_UnknownFrameInserted(aPresContext, aDesiredSize, aReflowState,
+                                        aStatus, (nsIFrame*)aAppendedFrame, PR_FALSE);
+  if (NS_FAILED(rv))
+    return rv;
 
   // account for the cells in the rows that are children of aAppendedFrame
-  nsresult rv = DidAppendRowGroup((nsTableRowGroupFrame*)aAppendedFrame);
+  rv = DidAppendRowGroup((nsTableRowGroupFrame*)aAppendedFrame);
 
   // do a pass-1 layout of all the cells in all the rows of the rowgroup
-  InvalidateFirstPassCache();
+  rv = ResizeReflowPass1(aPresContext, aDesiredSize, aReflowState.reflowState, aStatus, 
+                         aAppendedFrame, eReflowReason_Initial);
+  if (NS_FAILED(rv))
+    return rv;
 
-  // if any column widths have to change due to this, re-init the layout strategy
-  // mTableLayoutStrategy->Initialize(aDesiredSize.aMaxElementSize);  //XXX for now, we're just doing the whole enchelada
+  // if any column widths have to change due to this, rebalance column widths
+  mTableLayoutStrategy->Initialize(aDesiredSize.maxElementSize);  
 
   return rv;
 }
diff --git a/mozilla/layout/tables/nsTableFrame.h b/mozilla/layout/tables/nsTableFrame.h
index 05aacc6df15..021aca9fc3a 100644
--- a/mozilla/layout/tables/nsTableFrame.h
+++ b/mozilla/layout/tables/nsTableFrame.h
@@ -22,6 +22,8 @@
 #include "nsContainerFrame.h"
 #include "nsStyleCoord.h"
 #include "nsStyleConsts.h"
+#include "nsIFrameReflow.h"   // for nsReflowReason enum
+
 
 class nsCellMap;
 class nsVoidArray;
@@ -269,13 +271,17 @@ protected:
     * Pass 1 only needs to be executed once no matter how many times the table is resized, 
     * as long as content and style don't change.  This is managed in the member variable mFirstPassIsValid.
     * The layout information for each cell is cached in mColumLayoutData.
+    * Incremental layout can take advantage of aStartingFrame to pick up where a previous
+    * ResizeReflowPass1 left off.
     *
     * @see Reflow
     */
   NS_IMETHOD ResizeReflowPass1(nsIPresContext&          aPresContext,
                                nsHTMLReflowMetrics&     aDesiredSize,
                                const nsHTMLReflowState& aReflowState,
-                               nsReflowStatus&          aStatus);
+                               nsReflowStatus&          aStatus,
+                               nsTableRowGroupFrame *   aStartingFrame,
+                               nsReflowReason           aReason);
 
   /** second pass of ResizeReflow.
     * lays out all table content with aMaxSize(computed_table_width, given_table_height) 
@@ -298,10 +304,10 @@ protected:
     *
     * @see Reflow
     */
-  NS_IMETHOD IncrementalReflow(nsIPresContext&      aPresContext,
-                               nsHTMLReflowMetrics& aDesiredSize,
+  NS_IMETHOD IncrementalReflow(nsIPresContext&          aPresContext,
+                               nsHTMLReflowMetrics&     aDesiredSize,
                                const nsHTMLReflowState& aReflowState,
-                               nsReflowStatus&      aStatus);
+                               nsReflowStatus&          aStatus);
 
   NS_IMETHOD IR_TargetIsChild(nsIPresContext&        aPresContext,
                               nsHTMLReflowMetrics&   aDesiredSize,
diff --git a/mozilla/layout/tables/nsTableRowGroupFrame.cpp b/mozilla/layout/tables/nsTableRowGroupFrame.cpp
index 09df6333da1..8ffa859632a 100644
--- a/mozilla/layout/tables/nsTableRowGroupFrame.cpp
+++ b/mozilla/layout/tables/nsTableRowGroupFrame.cpp
@@ -606,8 +606,11 @@ void nsTableRowGroupFrame::ShrinkWrapChildren(nsIPresContext* aPresContext,
         cellFrame->GetStyleData(eStyleStruct_Display, ((nsStyleStruct *&)childDisplay));
         if (NS_STYLE_DISPLAY_TABLE_CELL == childDisplay->mDisplay)
         {
-          PRInt32 rowSpan = ((nsTableFrame*)mGeometricParent)->
-                                GetEffectiveRowSpan(rowIndex,(nsTableCellFrame*)cellFrame);
+          nsTableFrame *tableFrame=nsnull;
+          nsresult rv = nsTableFrame::GetTableFrame(this, tableFrame);
+          if (NS_FAILED(rv) || nsnull==tableFrame)
+            return;
+          PRInt32 rowSpan = tableFrame->GetEffectiveRowSpan(rowIndex,(nsTableCellFrame*)cellFrame);
           if (rowSpan > 1)
           { // found a cell with rowspan > 1, determine its height
             nscoord heightOfRowsSpanned = 0;