Hi Lorenzo,

Thank you for reporting this behavior. I investigated further and can confirm the observed behavior is a bug. I have converted this item to a Bug Report and have logged an item in the public repository. You could monitor the progress here:

https://github.com/telerik/kendo-ui-core/issues/5626

As a workaround, I would suggest adding the below configuration to the drop event handler:

drop:function(e){
    if(e.items.length == 0){
        e.preventDefault();
    }
}

Here is a dojo demonstrating the above suggestion implemented.

Finally, as a small token of gratitude for helping us identify this issue I have updated your Telerik Points.

Regards,
Aleksandar
Progress Telerik