--- a/widget/src/cocoa/nsNativeThemeCocoa.mm
+++ b/widget/src/cocoa/nsNativeThemeCocoa.mm
@@ -967,17 +967,17 @@ nsNativeThemeCocoa::DrawDropdown(CGConte
 
   [mDropdownCell setPullsDown:(aWidgetType == NS_THEME_BUTTON)];
 
   BOOL isEditable = (aWidgetType == NS_THEME_DROPDOWN_TEXTFIELD);
   NSCell* cell = isEditable ? (NSCell*)mComboBoxCell : (NSCell*)mDropdownCell;
 
   [cell setEnabled:!IsDisabled(aFrame)];
   [cell setShowsFirstResponder:(IsFocused(aFrame) || (inState & NS_EVENT_STATE_FOCUS))];
-  [cell setHighlighted:((inState & NS_EVENT_STATE_ACTIVE) && (inState & NS_EVENT_STATE_HOVER))];
+  [cell setHighlighted:IsOpenButton(aFrame)];
   [cell setControlTint:(FrameIsInActiveWindow(aFrame) ? [NSColor currentControlTint] : NSClearControlTint)];
 
   const CellRenderSettings& settings = isEditable ? editableMenulistSettings : dropdownSettings;
   DrawCellWithSnapping(cell, cgContext, inBoxRect, settings,
                        0.5f, mCellDrawView, IsFrameRTL(aFrame));
 
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
@@ -2360,17 +2360,18 @@ nsNativeThemeCocoa::WidgetStateChanged(n
     *aShouldRepaint = PR_FALSE;
     if (aAttribute == nsWidgetAtoms::disabled ||
         aAttribute == nsWidgetAtoms::checked ||
         aAttribute == nsWidgetAtoms::selected ||
         aAttribute == nsWidgetAtoms::mozmenuactive ||
         aAttribute == nsWidgetAtoms::sortdirection ||
         aAttribute == nsWidgetAtoms::focused ||
         aAttribute == nsWidgetAtoms::_default ||
-        aAttribute == nsWidgetAtoms::step)
+        aAttribute == nsWidgetAtoms::step ||
+        aAttribute == nsWidgetAtoms::open)
       *aShouldRepaint = PR_TRUE;
   }
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsNativeThemeCocoa::ThemeChanged()