diff --git a/mozilla/layout/html/table/src/BasicTableLayoutStrategy.cpp b/mozilla/layout/html/table/src/BasicTableLayoutStrategy.cpp
index 69d2994bec3..a2c1e4c74ec 100644
--- a/mozilla/layout/html/table/src/BasicTableLayoutStrategy.cpp
+++ b/mozilla/layout/html/table/src/BasicTableLayoutStrategy.cpp
@@ -16,7 +16,6 @@
  * Reserved.
  */
 
-#include <stdio.h>
 #include "BasicTableLayoutStrategy.h"
 #include "nsTableFrame.h"
 #include "nsTableColFrame.h"
@@ -946,8 +945,12 @@ PRBool BasicTableLayoutStrategy::BalanceColumnsTableFits(nsIPresContext* aPresCo
       {
         PRInt32 colIndex = autoColumns[i];
         nscoord oldColWidth = mTableFrame->GetColumnWidth(colIndex);
-        float percent = (float)oldColWidth/(float)totalWidthOfAutoColumns;
-        nscoord excessForThisColumn = excess*percent;
+        float percent;
+        if (0!=totalWidthOfAutoColumns)
+          percent = (float)oldColWidth/(float)totalWidthOfAutoColumns;
+        else
+          percent = (float)1/(float)numAutoColumns;
+        nscoord excessForThisColumn = (nscoord)(excess*percent);
         nscoord colWidth = excessForThisColumn+oldColWidth;
         if (gsDebug==PR_TRUE) 
           printf("  column %d was %d, now set to %d\n", colIndex, mTableFrame->GetColumnWidth(colIndex), colWidth);
diff --git a/mozilla/layout/html/table/src/nsTableCellFrame.cpp b/mozilla/layout/html/table/src/nsTableCellFrame.cpp
index 5c4715ebac7..32d65141b02 100644
--- a/mozilla/layout/html/table/src/nsTableCellFrame.cpp
+++ b/mozilla/layout/html/table/src/nsTableCellFrame.cpp
@@ -367,6 +367,25 @@ NS_METHOD nsTableCellFrame::Reflow(nsIPresContext* aPresContext,
   cellWidth = kidSize.width;  // at this point, we've factored in the cell's style attributes
   if (NS_UNCONSTRAINEDSIZE!=cellWidth)
     cellWidth += leftInset + rightInset;
+  // Nav4 hack for 0 width cells.  If the cell has any content, it must have a desired width of at least 1
+  if (0==cellWidth)
+  {
+    PRInt32 childCount;
+    mFirstChild->ChildCount(childCount);
+    if (0!=childCount)
+    {
+      nsIFrame *grandChild;
+      mFirstChild->FirstChild(grandChild);
+      grandChild->ChildCount(childCount);
+      if (0!=childCount)
+      {
+        cellWidth=1;
+        if (nsnull!=aDesiredSize.maxElementSize && 0==pMaxElementSize->width)
+          pMaxElementSize->width=1;
+      }
+    }
+  }
+  // end Nav4 hack for 0 width cells
 
   // set the cell's desired size and max element size
   aDesiredSize.width = cellWidth;
diff --git a/mozilla/layout/html/table/src/nsTableFrame.cpp b/mozilla/layout/html/table/src/nsTableFrame.cpp
index 676acd42d0b..5ee03026a6e 100644
--- a/mozilla/layout/html/table/src/nsTableFrame.cpp
+++ b/mozilla/layout/html/table/src/nsTableFrame.cpp
@@ -2160,13 +2160,18 @@ void nsTableFrame::BalanceColumnWidths(nsIPresContext* aPresContext,
   case eStyleUnit_Coord:
     maxWidth = position->mWidth.GetCoordValue();
     break;
+
+  case eStyleUnit_Auto:
+    maxWidth = aMaxSize.width;
+    break;
+
   case eStyleUnit_Percent:
   case eStyleUnit_Proportional:
+  case eStyleUnit_Inherit:
     // XXX for now these fall through
 
   default:
-  case eStyleUnit_Auto:
-  case eStyleUnit_Inherit:
+
     maxWidth = aMaxSize.width;
     break;
   }
diff --git a/mozilla/layout/tables/BasicTableLayoutStrategy.cpp b/mozilla/layout/tables/BasicTableLayoutStrategy.cpp
index 69d2994bec3..a2c1e4c74ec 100644
--- a/mozilla/layout/tables/BasicTableLayoutStrategy.cpp
+++ b/mozilla/layout/tables/BasicTableLayoutStrategy.cpp
@@ -16,7 +16,6 @@
  * Reserved.
  */
 
-#include <stdio.h>
 #include "BasicTableLayoutStrategy.h"
 #include "nsTableFrame.h"
 #include "nsTableColFrame.h"
@@ -946,8 +945,12 @@ PRBool BasicTableLayoutStrategy::BalanceColumnsTableFits(nsIPresContext* aPresCo
       {
         PRInt32 colIndex = autoColumns[i];
         nscoord oldColWidth = mTableFrame->GetColumnWidth(colIndex);
-        float percent = (float)oldColWidth/(float)totalWidthOfAutoColumns;
-        nscoord excessForThisColumn = excess*percent;
+        float percent;
+        if (0!=totalWidthOfAutoColumns)
+          percent = (float)oldColWidth/(float)totalWidthOfAutoColumns;
+        else
+          percent = (float)1/(float)numAutoColumns;
+        nscoord excessForThisColumn = (nscoord)(excess*percent);
         nscoord colWidth = excessForThisColumn+oldColWidth;
         if (gsDebug==PR_TRUE) 
           printf("  column %d was %d, now set to %d\n", colIndex, mTableFrame->GetColumnWidth(colIndex), colWidth);
diff --git a/mozilla/layout/tables/nsTableCellFrame.cpp b/mozilla/layout/tables/nsTableCellFrame.cpp
index 5c4715ebac7..32d65141b02 100644
--- a/mozilla/layout/tables/nsTableCellFrame.cpp
+++ b/mozilla/layout/tables/nsTableCellFrame.cpp
@@ -367,6 +367,25 @@ NS_METHOD nsTableCellFrame::Reflow(nsIPresContext* aPresContext,
   cellWidth = kidSize.width;  // at this point, we've factored in the cell's style attributes
   if (NS_UNCONSTRAINEDSIZE!=cellWidth)
     cellWidth += leftInset + rightInset;
+  // Nav4 hack for 0 width cells.  If the cell has any content, it must have a desired width of at least 1
+  if (0==cellWidth)
+  {
+    PRInt32 childCount;
+    mFirstChild->ChildCount(childCount);
+    if (0!=childCount)
+    {
+      nsIFrame *grandChild;
+      mFirstChild->FirstChild(grandChild);
+      grandChild->ChildCount(childCount);
+      if (0!=childCount)
+      {
+        cellWidth=1;
+        if (nsnull!=aDesiredSize.maxElementSize && 0==pMaxElementSize->width)
+          pMaxElementSize->width=1;
+      }
+    }
+  }
+  // end Nav4 hack for 0 width cells
 
   // set the cell's desired size and max element size
   aDesiredSize.width = cellWidth;
diff --git a/mozilla/layout/tables/nsTableFrame.cpp b/mozilla/layout/tables/nsTableFrame.cpp
index 676acd42d0b..5ee03026a6e 100644
--- a/mozilla/layout/tables/nsTableFrame.cpp
+++ b/mozilla/layout/tables/nsTableFrame.cpp
@@ -2160,13 +2160,18 @@ void nsTableFrame::BalanceColumnWidths(nsIPresContext* aPresContext,
   case eStyleUnit_Coord:
     maxWidth = position->mWidth.GetCoordValue();
     break;
+
+  case eStyleUnit_Auto:
+    maxWidth = aMaxSize.width;
+    break;
+
   case eStyleUnit_Percent:
   case eStyleUnit_Proportional:
+  case eStyleUnit_Inherit:
     // XXX for now these fall through
 
   default:
-  case eStyleUnit_Auto:
-  case eStyleUnit_Inherit:
+
     maxWidth = aMaxSize.width;
     break;
   }