Rename menu item to avoid confusion

package.json

@@ -87,7 +87,7 @@
         "c9.ide.navigate": "#64156c7f4a",
         "c9.ide.newresource": "#9a7464cc47",
         "c9.ide.openfiles": "#28a4f5af16",
-        "c9.ide.preview": "#3c4dded23f",
+        "c9.ide.preview": "#f6d1bd9921",
         "c9.ide.preview.browser": "#be197b0464",
         "c9.ide.preview.markdown": "#bf952685f6",
         "c9.ide.pubsub": "#92ec19ed3a",