Index: mozilla/layout/xul/base/src/tree/src/nsTreeContentView.cpp
===================================================================
RCS file: /cvsroot/mozilla/layout/xul/base/src/tree/src/nsTreeContentView.cpp,v
retrieving revision 1.56
diff -pU10 -r1.56 mozilla/layout/xul/base/src/tree/src/nsTreeContentView.cpp
--- mozilla/layout/xul/base/src/tree/src/nsTreeContentView.cpp
+++ mozilla/layout/xul/base/src/tree/src/nsTreeContentView.cpp
@@ -1442,39 +1442,56 @@ nsTreeContentView::UpdateParentIndexes(P
     Row* row = (Row*)mRows[i];
     if (row->mParentIndex > aIndex) {
       row->mParentIndex += aCount;
     }
   }
 }
 
 nsIContent*
 nsTreeContentView::GetCell(nsIContent* aContainer, nsITreeColumn* aCol)
 {
-  const PRUnichar* colID;
+  nsString colID;
   PRInt32 colIndex;
-  aCol->GetIdConst(&colID);
+  aCol->GetId(colID);
   aCol->GetIndex(&colIndex);
 
   // Traverse through cells, try to find the cell by "ref" attribute or by cell
   // index in a row. "ref" attribute has higher priority.
   nsIContent* result = nsnull;
   PRInt32 j = 0;
   ChildIterator iter, last;
-  for (ChildIterator::Init(aContainer, &iter, &last); iter != last; ++iter) {
-    nsCOMPtr<nsIContent> cell = *iter;
-
-    if (cell->Tag() == nsXULAtoms::treecell) {
-      if (colID[0] != 0 && cell->AttrValueIs(kNameSpaceID_None, nsXULAtoms::ref,
-                                             nsDependentString(colID),
-                                             eCaseMatters)) {
-        result = cell;
-        break;
+  ChildIterator::Init(aContainer, &iter, &last);
+  nsCOMPtr<nsIContent> cell;
+  if (!colID.IsEmpty()) {
+    while (iter != last) {
+      cell = *iter;
+      if (cell->Tag() == nsXULAtoms::treecell) {
+        if (cell->AttrValueIs(kNameSpaceID_None, nsXULAtoms::ref,
+                              colID,
+                              eCaseMatters)) {
+          result = cell;
+          break;
+        }
+        else if (j == colIndex) {
+          result = cell;
+          break;
+        }
+        ++j;
       }
-      else if (j == colIndex) {
-        result = cell;
+      ++iter;
+    }
+  } else {
+    while (iter != last) {
+      cell = *iter;
+      if (cell->Tag() == nsXULAtoms::treecell) {
+        if (j == colIndex) {
+          result = cell;
+          break;
+        }
+        ++j;
       }
-      j++;
+      ++iter;
     }
   }
 
   return result;
 }