 <p>I assume pageTabPanel isn't defined at the time you trigger the handler. Try to remove the var keyword in front of "var pageTabPanel =" to make it a global variable.</p> <p>If that works, it's a scope/variable issue. The better solution is to give the tabpanel an id and call Ext.getCmp('tabpanelid').render('contentpanel') in your renderPageTabs method.</p> <p>Hope that helps.</p> <p>Regards, Steffen</p>