--- a/layout/forms/nsComboboxControlFrame.cpp
+++ b/layout/forms/nsComboboxControlFrame.cpp
@@ -1287,16 +1287,23 @@ public:
     : nsBlockFrame(aContext),
       mComboBox(aComboBox)
   {}
 
   // Need this so that line layout knows that this block's inline size
   // depends on the available inline size.
   virtual nsIAtom* GetType() const override;
 
+#ifdef DEBUG_FRAME_DUMP
+  nsresult GetFrameName(nsAString& aResult) const
+  {
+    return MakeFrameName(NS_LITERAL_STRING("ComboboxDisplay"), aResult);
+  }
+#endif
+
   virtual bool IsFrameOfType(uint32_t aFlags) const override
   {
     return nsBlockFrame::IsFrameOfType(aFlags &
       ~(nsIFrame::eReplacedContainsBlock));
   }
 
   virtual void Reflow(nsPresContext*           aPresContext,
                           ReflowOutput&     aDesiredSize,