diff --git a/common/content/buffer.js b/common/content/buffer.js
index 621f80c0..6e57c834 100644
--- a/common/content/buffer.js
+++ b/common/content/buffer.js
@@ -90,7 +90,7 @@ function Buffer() //{{{
                 let borderSize = parseInt(style[border1]) + parseInt(style[border2]);
                 let realSize = elem[size];
                 // Stupid Gecko eccentricities. May fail for quirks mode documents.
-                if (elem[size] + borderSize == elem[layoutSize] || elem[size] == 0) // Stupid, fallible heuristic.
+                if (elem[size] + borderSize == elem[max] || elem[size] == 0) // Stupid, fallible heuristic.
                     continue;
                 if (style[overflow] == "hidden")
                     realSize += borderSize;