diff --git a/src/emu.js b/src/emu.js
index fd62467d..259e4145 100644
--- a/src/emu.js
+++ b/src/emu.js
@@ -202,7 +202,7 @@ var AnimationTimer = function(frequencyHz, callback) {
   var intervalMsec = 1000.0 / frequencyHz;
   var running;
   var lastts = 0;
-  var useReqAnimFrame = true;
+  var useReqAnimFrame = window.requestAnimationFrame ? true : false;
 
   function scheduleFrame() {
     if (useReqAnimFrame)
diff --git a/src/ui.js b/src/ui.js
index a8c2e587..95f9d67e 100644
--- a/src/ui.js
+++ b/src/ui.js
@@ -1064,7 +1064,7 @@ function openBitmapEditorAtCursor() {
     editor.setSelection(data.end, data.start);
     openBitmapEditorWithParams(data.obj, editor.getSelection(), paldata, palbytestr);
   } else {
-    alert("No bitmap spec found in format /*{w:,h:,bpp:,count:...}*/");
+    alert("To edit graphics, move cursor to a constant array preceded by a comment in the format:\n\n/*{w:,h:,bpp:,count:...}*/\n\n(See code examples)");
   }
 }
 
diff --git a/testemu.html b/testemu.html
index ebb2aa73..c002a63c 100644
--- a/testemu.html
+++ b/testemu.html
@@ -30,7 +30,7 @@
     <script src="jquery/jquery-2.2.3.min.js"></script>
 
     <script src="javatari.js/release/javatari/javatari.js"></script>
-    <script src="src/cpu/z80.js"></script>
+    <script src="src/cpu/z80fast.js"></script>
     <script src="src/emu.js"></script>
     <script src="src/util.js"></script>
     <script src="src/disasm.js"></script>