diff --git a/blocks.js b/blocks.js
index 2280501e..4501b0fe 100644
--- a/blocks.js
+++ b/blocks.js
@@ -155,7 +155,7 @@ DialogBoxMorph, BlockInputFragmentMorph, PrototypeHatBlockMorph*/
 
 // Global stuff ////////////////////////////////////////////////////////
 
-modules.blocks = '2013-July-09';
+modules.blocks = '2013-July-11';
 
 var SyntaxElementMorph;
 var BlockMorph;
@@ -4418,6 +4418,7 @@ ScriptsMorph.prototype.step = function () {
 
     if (this.feedbackMorph.parent) {
         this.feedbackMorph.destroy();
+        this.feedbackMorph.parent = null;
     }
     if (hand.children.length === 0) {
         return null;
diff --git a/history.txt b/history.txt
index ceaf1d67..6140b943 100755
--- a/history.txt
+++ b/history.txt
@@ -1799,3 +1799,7 @@ ______
 130710
 ------
 * GUI: Reset hidden primitives and code mappings upon loading a new project
+
+130711
+------
+* Blocks: fixed occasional flickering in scripting areas (caused by deleted feedback morphs, a bug that surfaced in Chrome 28 on OSX and may be due to a possible Chrome GC issue)