--- Revision 515
+++ Revision 572
@@ -149,6 +149,10 @@
       this.modalOverlay.setStyle("height: " + this.viewport.getHeight() + "px");
       
       this.options.showOverlay(this.modalOverlay, {from: 0, to: this.modalOverlay.opacity});
+      if (this.iframe) {
+        this.iframe.setBounds({top: 0, left: 0, width: this.viewport.getWidth(), height: this.viewport.getHeight()});
+        this.iframe.show();
+      }
     }
     this.modalOverlay.setStyle({ zIndex: win.zIndex - 1 });
     this.modalSessions++;
@@ -161,6 +165,8 @@
     } else {
       this.resetOverflow();
       this.options.hideOverlay(this.modalOverlay, { from: this.modalOverlay.opacity, to: 0 });
+      if (this.iframe) 
+        this.iframe.hide();
     }
   },
   
@@ -267,6 +273,7 @@
   createOverlays: function() {
     this.modalOverlay = new Element("div", { style: this.overlayStyle });
     this.dragOverlay  = new Element("div", { style: this.overlayStyle+"height: 100%" });
+    this.iframe       = Prototype.Browser.IE ? new UI.IframeShim() : null;
   },
   
   focus: function(win) {