diff --git a/lib/ace/lib/keys.js b/lib/ace/lib/keys.js
index 70e4ccb2..c4cc3f31 100644
--- a/lib/ace/lib/keys.js
+++ b/lib/ace/lib/keys.js
@@ -148,7 +148,11 @@ var Keys = (function() {
 oop.mixin(exports, Keys);
 
 exports.keyCodeToString = function(keyCode) {
-    return (Keys[keyCode] || String.fromCharCode(keyCode)).toLowerCase();
+    // Language-switching keystroke in Chrome/Linux emits keyCode 0.
+    var keyString = Keys[keyCode];
+    if (typeof keyString != "string")
+        keyString = String.fromCharCode(keyCode);
+    return keyString.toLowerCase();
 };
 
 });