diff --git a/IPython/html/static/notebook/js/textcell.js b/IPython/html/static/notebook/js/textcell.js
index fd9f7da..71e604a 100644
--- a/IPython/html/static/notebook/js/textcell.js
+++ b/IPython/html/static/notebook/js/textcell.js
@@ -163,6 +163,7 @@ define([
      * */
     TextCell.prototype.set_text = function(text) {
         this.code_mirror.setValue(text);
+        this.unrender();
         this.code_mirror.refresh();
     };
 
diff --git a/IPython/html/tests/notebook/markdown.js b/IPython/html/tests/notebook/markdown.js
index 0c1f61e..5f28d31 100644
--- a/IPython/html/tests/notebook/markdown.js
+++ b/IPython/html/tests/notebook/markdown.js
@@ -17,20 +17,31 @@ casper.notebook_test(function () {
         $('#to_code').mouseenter().click();
         $('#to_markdown').mouseenter().click();
         var cell = IPython.notebook.get_selected_cell();
-        cell.set_text('# Foo');
+        cell.set_text('# Bar');
         $('#run_cell').mouseenter().click();
         return cell.get_rendered();
     });
-    this.test.assertEquals(output.trim(), '<h1 id=\"foo\">Foo</h1>', 'Markdown menubar items work.');
+    this.test.assertEquals(output.trim(), '<h1 id=\"bar\">Bar</h1>', 'Markdown menubar items work.');
     
     // Test toolbar buttons.
     output = this.evaluate(function () {
         $('#cell_type').val('code').change();
         $('#cell_type').val('markdown').change();
         var cell = IPython.notebook.get_selected_cell();
-        cell.set_text('# Foo');
+        cell.set_text('# Baz');
         $('#run_b').click();
         return cell.get_rendered();
     });
-    this.test.assertEquals(output.trim(), '<h1 id=\"foo\">Foo</h1>', 'Markdown toolbar items work.');
+    this.test.assertEquals(output.trim(), '<h1 id=\"baz\">Baz</h1>', 'Markdown toolbar items work.');
+    
+    // Test JavaScript models.
+    var output = this.evaluate(function () {
+
+        var cell = IPython.notebook.insert_cell_at_index('markdown', 0);
+        cell.set_text('# Qux');
+        cell.render();
+        return cell.get_rendered();
+    });
+    this.test.assertEquals(output.trim(), '<h1 id=\"qux\">Qux</h1>', 'Markdown JS API works.');
+    
 });