Thank you for sharing this idea. You will find your Telerik points updated, and for the time being I can suggest you try to implement the handlers with your own code, here's an example that seems to work across windows of the same browser for me: https://decafbad.com/2009/07/drag-and-drop/api-demos.html#delegated. The Kendo widgets expose data attributes and you can traverse the DOM to get relevant items/data, so you may still be able to implement a similar drag-and-drop feature in your project that allows for transfer of the required data even without a feature built-in into the Kendo widgets.