diff --git a/src/gui.js b/src/gui.js
index a53c21e8..ac0413cb 100644
--- a/src/gui.js
+++ b/src/gui.js
@@ -381,6 +381,11 @@ IDE_Morph.prototype.openIn = function (world) {
         if (dict.noExitWarning) {
             window.onbeforeunload = nop;
         }
+        if (dict.blocksZoom) {
+            myself.savingPreferences = false;
+            myself.setBlocksScale(Math.max(1,Math.min(dict.blocksZoom, 12)));
+            myself.savingPreferences = true;
+        }
 
         // only force my world to get focus if I'm not in embed mode
         // to prevent the iFrame from involuntarily scrolling into view