Mr. SA Supporter please check why this modules allways works fine for you in ie9 and don't for other users, at least for this topic people, well how already said before, Zoo Category Accordiom is working in Chrome, Firefox etc, but never in IE9 (strangelly it have worked sometimes when i reloaded the page after activate the F12 key IE developer tool, why? I don't mean... This k2 categories accordion module is identical, and works perfect in IE9, maybe you can clone this code to test with the zoo. Take a look at my posted video and have the prove youtu.be/TZwIAmOh84Q zoo module works fine in IE only for you, theres something wrong with all other people or something extremally perfect in your computer. Best regards!