Update index.htm

Author: Bernardo-Castilho

demo/index.htm

@@ -65,6 +65,7 @@ <h2>
         <wj-flex-grid style="max-height:200px"
                       control="flex"
                       items-source="data">
+            <wj-flex-grid-filter></wj-flex-grid-filter>
         </wj-flex-grid>
 
         <h2>