declare namespace Ext {
    export namespace tree {
        export interface ViewDropZoneConfig {
            allowContainerDrops?: boolean;
            allowParentInserts?: boolean;
            appendOnly?: boolean;
            containerScroll?: boolean;
            ddGroup?: string;
            dropAllowed?: string;
            dropNotAllowed?: string;
            expandDelay?: number;
            overClass?: string;
        }

        export class ViewDropZone extends Ext.view.DropZone  {
        }
    }
}