I just spent a few minutes reading and debugging some JavaScript code that renders an ExtJS TabPanel... Oddly, IE 6 and IE 7 rendered the TabPanel twice, including the tabs. It turned out to be the name of the JavaScript variable used for the TabPanel: [code="javascript"] tabs = new Ext.TabPanel({ [/code] Making the minor name change fixed it: [code="javascript"] huh = new Ext.TabPanel({ [/code]