--- a/layout/tables/nsTableFrame.cpp
+++ b/layout/tables/nsTableFrame.cpp
@@ -268,17 +268,17 @@ nsTableFrame::DestroyPositionedTablePart
 
 /* static */ void
 nsTableFrame::RegisterPositionedTablePart(nsIFrame* aFrame)
 {
   // Supporting relative positioning for table parts other than table cells has
   // the potential to break sites that apply 'position: relative' to those
   // parts, expecting nothing to happen. We warn at the console to make tracking
   // down the issue easy.
-  if (nsGkAtoms::tableCellFrame != aFrame->GetType()) {
+  if (!IS_TABLE_CELL(aFrame->GetType())) {
     nsIContent* content = aFrame->GetContent();
     nsPresContext* presContext = aFrame->PresContext();
     if (content && !presContext->HasWarnedAboutPositionedTableParts()) {
       presContext->SetHasWarnedAboutPositionedTableParts();
       nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
                                       NS_LITERAL_CSTRING("Layout: Tables"),
                                       content->OwnerDoc(),
                                       nsContentUtils::eLAYOUT_PROPERTIES,