diff --git a/src/LiveDevelopment/Agents/CSSAgent.js b/src/LiveDevelopment/Agents/CSSAgent.js
index <HASH>..<HASH> 100644
--- a/src/LiveDevelopment/Agents/CSSAgent.js
+++ b/src/LiveDevelopment/Agents/CSSAgent.js
@@ -67,7 +67,11 @@ define(function CSSAgent(require, exports, module) {
      * @param {string} url
      */
     function styleForURL(url) {
-        return _urlToStyle[_canonicalize(url)];
+        if (_urlToStyle) {
+            return _urlToStyle[_canonicalize(url)];
+        }
+        
+        return null;
     }
 
     /** Get a list of all loaded stylesheet files by URL */
diff --git a/src/LiveDevelopment/LiveDevelopment.js b/src/LiveDevelopment/LiveDevelopment.js
index <HASH>..<HASH> 100644
--- a/src/LiveDevelopment/LiveDevelopment.js
+++ b/src/LiveDevelopment/LiveDevelopment.js
@@ -923,7 +923,7 @@ define(function LiveDevelopment(require, exports, module) {
             return false;
         }
 
-        return true;
+        return _isHtmlFileExt(localPath);
     };
 
     /**
safe fix for #<I>. only support live preview for known subset of HTML document extensions.