--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -2316,17 +2316,18 @@ nsStyleImageLayers::CalcDifference(const
       }
     }
   }
 
   if (hint) {
     return hint;
   }
 
-  if (mBlendModeCount != aOther.mBlendModeCount ||
+  if (mAttachmentCount != aOther.mAttachmentCount ||
+      mBlendModeCount != aOther.mBlendModeCount ||
       mClipCount != aOther.mClipCount ||
       mCompositeCount != aOther.mCompositeCount ||
       mMaskModeCount != aOther.mMaskModeCount ||
       mOriginCount != aOther.mOriginCount ||
       mRepeatCount != aOther.mRepeatCount ||
       mPositionCount != aOther.mPositionCount ||
       mSizeCount != aOther.mSizeCount) {
     NS_UpdateHint(hint, nsChangeHint_NeutralChange);