Index: wp-includes/js/tinymce/plugins/wordpress/editor_plugin.dev.js
===================================================================
--- wp-includes/js/tinymce/plugins/wordpress/editor_plugin.dev.js	(revision 12807)
+++ wp-includes/js/tinymce/plugins/wordpress/editor_plugin.dev.js	(working copy)
@@ -19,7 +19,7 @@
 			// Hides the specified toolbar and resizes the iframe
 			ed.onPostRender.add(function() {
 				var adv_toolbar = ed.controlManager.get(tbId);
-				if ( ed.getParam('wordpress_adv_hidden', 1) && adv_toolbar ) {
+				if ( parseInt(ed.getParam('wordpress_adv_hidden', 1)) && adv_toolbar ) {
 					DOM.hide(adv_toolbar.id);
 					t._resizeIframe(ed, tbId, 28);
 				}