Provide the ability to drag/drop files into the Treeview/GridView of RadFileExplorer and automatically upload them. Currently this option is offered only over the RadAsyncUpload area inside the Upload dialog of RadFileExplorer.
This functionality has been introduced in Q2 2015. Release notes - http://www.telerik.com/support/whats-new/aspnet-ajax/release-history/ui-for-asp-net-ajax-q2-2015-version-2015-2-623 - Added Enable drag and drop file upload in RadEditor's FileBrowser dialogs
that's possible with the custom drop zones of the AsyncUpload http://demos.telerik.com/aspnet-ajax/asyncupload/examples/draganddrop/defaultcs.aspx