I would like to clarify that we are not aware of such problem with a third party tool and our RadScheduler control. Most probably a client-side error is preventing user interaction with the RadScheduler control.
I noticed that Mango chat tool includes and uses a jQuery and it is quite possible that this issue is due to jQuery conflict. in this help article
you may find information what version of jQuery we are using in each release version. Based on the information you ca try to update the jQuery version of your chat tool with the jQuery version used in your current RadControls release. In order to avoid any problems with latest version of IE (10 and 11) we highly recommend updating to the latest official version.
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