diff --git a/package.json b/package.json
index d7540477b..c04928eec 100644
--- a/package.json
+++ b/package.json
@@ -45,6 +45,6 @@
     "tap": "10.1.0",
     "travis-after-all": "1.4.4",
     "webpack": "2.2.1",
-    "webpack-dev-server": "1.16.3"
+    "webpack-dev-server": "2.3.0"
   }
 }
diff --git a/src/blocks/scratch3_control.js b/src/blocks/scratch3_control.js
index 28737b361..285b241ab 100644
--- a/src/blocks/scratch3_control.js
+++ b/src/blocks/scratch3_control.js
@@ -110,7 +110,7 @@ Scratch3ControlBlocks.prototype.stop = function (args, util) {
         option === 'other scripts in stage') {
         util.stopOtherTargetThreads();
     } else if (option === 'this script') {
-        util.stopThread();
+        util.stopThisScript();
     }
 };
 
diff --git a/src/blocks/scratch3_pen.js b/src/blocks/scratch3_pen.js
index c8f98341e..9b9f64919 100644
--- a/src/blocks/scratch3_pen.js
+++ b/src/blocks/scratch3_pen.js
@@ -147,6 +147,7 @@ Scratch3PenBlocks.prototype._updatePenColor = function (penState) {
     penState.penAttributes.color4f[0] = rgb.r / 255.0;
     penState.penAttributes.color4f[1] = rgb.g / 255.0;
     penState.penAttributes.color4f[2] = rgb.b / 255.0;
+    penState.penAttributes.color4f[3] = 1;
 };
 
 /**
@@ -260,6 +261,8 @@ Scratch3PenBlocks.prototype.setPenColorToColor = function (args, util) {
     penState.penAttributes.color4f[2] = rgb.b / 255.0;
     if (rgb.hasOwnProperty('a')) {  // Will there always be an 'a'?
         penState.penAttributes.color4f[3] = rgb.a / 255.0;
+    } else {
+        penState.penAttributes.color4f[3] = 1;
     }
 };
 
diff --git a/src/engine/execute.js b/src/engine/execute.js
index 44951aba3..226a866a7 100644
--- a/src/engine/execute.js
+++ b/src/engine/execute.js
@@ -183,8 +183,8 @@ var execute = function (sequencer, thread) {
         stopOtherTargetThreads: function () {
             runtime.stopForTarget(target, thread);
         },
-        stopThread: function () {
-            sequencer.retireThread(thread);
+        stopThisScript: function () {
+            thread.stopThisScript();
         },
         startProcedure: function (procedureCode) {
             sequencer.stepToProcedure(thread, procedureCode);
diff --git a/src/engine/thread.js b/src/engine/thread.js
index 9693b26f1..f093f886e 100644
--- a/src/engine/thread.js
+++ b/src/engine/thread.js
@@ -140,6 +140,27 @@ Thread.prototype.popStack = function () {
     return this.stack.pop();
 };
 
+/**
+ * Pop back down the stack frame until we hit a procedure call or the stack frame is emptied
+ */
+Thread.prototype.stopThisScript = function () {
+    var blockID = this.peekStack();
+    while (blockID !== null) {
+        var block = this.target.blocks.getBlock(blockID);
+        if (typeof block !== 'undefined' && block.opcode === 'procedures_callnoreturn') {
+            break;
+        }
+        this.popStack();
+        blockID = this.peekStack();
+    }
+
+    if (this.stack.length === 0) {
+        // Clean up!
+        this.requestScriptGlowInFrame = false;
+        this.status = Thread.STATUS_DONE;
+    }
+};
+
 /**
  * Get top stack item.
  * @return {?string} Block ID on top of stack.
diff --git a/src/util/timer.js b/src/util/timer.js
index 17c66a567..9a60e5688 100644
--- a/src/util/timer.js
+++ b/src/util/timer.js
@@ -23,16 +23,35 @@ var Timer = function () {};
  */
 Timer.prototype.startTime = 0;
 
+/**
+ * Disable use of self.performance for now as it results in lower performance
+ * However, instancing it like below (caching the self.performance to a local variable) negates most of the issues.
+ * @type {boolean}
+ */
+var USE_PERFORMANCE = false;
+
+/**
+ * Legacy object to allow for us to call now to get the old style date time (for backwards compatibility)
+ * @deprecated This is only called via the nowObj.now() if no other means is possible...
+ */
+var legacyDateCode = {
+    now: function () {
+        return new Date().getTime();
+    }
+};
+
+/**
+ * Use this object to route all time functions through single access points.
+ */
+var nowObj = (USE_PERFORMANCE && typeof self !== 'undefined' && self.performance && 'now' in self.performance) ?
+    self.performance : Date.now ? Date : legacyDateCode;
+
 /**
  * Return the currently known absolute time, in ms precision.
  * @returns {number} ms elapsed since 1 January 1970 00:00:00 UTC.
  */
 Timer.prototype.time = function () {
-    if (Date.now) {
-        return Date.now();
-    } else {
-        return new Date().getTime();
-    }
+    return nowObj.now();
 };
 
 /**
@@ -43,12 +62,7 @@ Timer.prototype.time = function () {
  * @returns {number} ms-scale accurate time relative to other relative times.
  */
 Timer.prototype.relativeTime = function () {
-    if (typeof self !== 'undefined' &&
-        self.performance && 'now' in self.performance) {
-        return self.performance.now();
-    } else {
-        return this.time();
-    }
+    return nowObj.now();
 };
 
 /**
@@ -56,15 +70,11 @@ Timer.prototype.relativeTime = function () {
  * at the most accurate precision possible.
  */
 Timer.prototype.start = function () {
-    this.startTime = this.relativeTime();
+    this.startTime = nowObj.now();
 };
 
-/**
- * Check time elapsed since `timer.start` was called.
- * @returns {number} Time elapsed, in ms (possibly sub-ms precision).
- */
 Timer.prototype.timeElapsed = function () {
-    return this.relativeTime() - this.startTime;
+    return nowObj.now() - this.startTime;
 };
 
 module.exports = Timer;
diff --git a/test/unit/blocks_control.js b/test/unit/blocks_control.js
index 2dc6049df..7867524ce 100644
--- a/test/unit/blocks_control.js
+++ b/test/unit/blocks_control.js
@@ -104,7 +104,7 @@ test('stop', function (t) {
     var state = {
         stopAll: 0,
         stopOtherTargetThreads: 0,
-        stopThread: 0
+        stopThisScript: 0
     };
     var util = {
         stopAll: function () {
@@ -113,8 +113,8 @@ test('stop', function (t) {
         stopOtherTargetThreads: function () {
             state.stopOtherTargetThreads++;
         },
-        stopThread: function () {
-            state.stopThread++;
+        stopThisScript: function () {
+            state.stopThisScript++;
         }
     };
 
@@ -125,6 +125,6 @@ test('stop', function (t) {
     c.stop({STOP_OPTION: 'this script'}, util);
     t.strictEqual(state.stopAll, 1);
     t.strictEqual(state.stopOtherTargetThreads, 2);
-    t.strictEqual(state.stopThread, 1);
+    t.strictEqual(state.stopThisScript, 1);
     t.end();
 });