Conflict with IE10…

Hi – upgraded my site (AgentPress Two theme) to 3.9 and there seems to be a conflict with the Widget Customizer that came included with the upgrade. While it works fine in Chrome, it doesn’t in IE10. The new (longer) menu on left isn’t expanded and the website view on rt only shows for a brief second before disappearing. I’ve already tried clearing cache etc. but no dice. Help?

https://www.ads-software.com/plugins/widget-customizer/