Ensure unique World stamps

history.txt

@@ -1670,3 +1670,7 @@ ______
 * Morphic: Introducing World.stamp as reference in multi-World setups
 * Widgets: restore multi-dialog restrictions for multi-world setups
 * Translation update for "hide primitives" feature
+
+130426
+------
+* Morphic: ensure unique World stamps

morphic.js

@@ -1035,7 +1035,7 @@
 /*global window, HTMLCanvasElement, getMinimumFontHeight, FileReader, Audio,
 FileList, getBlurredShadowSupport*/
 
-var morphicVersion = '2013-April-25';
+var morphicVersion = '2013-April-26';
 var modules = {}; // keep track of additional loaded modules
 var useBlurredShadows = getBlurredShadowSupport(); // check for Chrome-bug
 
@@ -9886,6 +9886,9 @@ WorldMorph.prototype.init = function (aCanvas, fillPage) {
 
     // additional properties:
     this.stamp = Date.now(); // reference in multi-world setups
+    while (this.stamp === Date.now()) {nop(); }
+    this.stamp = Date.now();
+
     this.useFillPage = fillPage;
     if (this.useFillPage === undefined) {
         this.useFillPage = true;