diff --git a/unpacked/jax/input/MathML/jax.js b/unpacked/jax/input/MathML/jax.js
index 58772053b..89f6c071b 100644
--- a/unpacked/jax/input/MathML/jax.js
+++ b/unpacked/jax/input/MathML/jax.js
@@ -142,8 +142,14 @@
         value = this.filterAttribute(name,value);
         var defaults = (mml.type === "mstyle" ? MML.math.prototype.defaults : mml.defaults);
         if (value != null) {
-          if (value.toLowerCase() === "true") {value = true}
-            else if (value.toLowerCase() === "false") {value = false}
+          var val = value.toLowerCase();
+          if (val === "true" || val === "false") {
+            if (typeof (defaults[name]) === "boolean" || defaults[name] === MML.INHERIT ||
+               (defaults[name] === MML.AUTO && 
+               (mml.defaultDef == null || typeof(mml.defaultDef[name]) === "boolean"))) {
+              value = (val === "true");
+            }
+          }
           if (defaults[name] != null || MML.copyAttributes[name])
             {mml[name] = value} else {mml.attr[name] = value}
           mml.attrNames.push(name);