es/dragdrop/DragManager.js
/**
     * @param refElement, the element being moved
     * @param draggingHtml, the element show in the dragging layer
     */
@param refElement, the element being moved
@param draggingHtml, the element show in the dragging layer
@param refElement the element being moved @param draggingHtml the element show in the dragging layer
startDrag(refElement, draggingHtml) {
        if (!this._init) {
            throw new Error('startDrag can only be used in onDragStart callback');
        }
        if (refElement === undefined) {
            refElement = this.component.element;
        }
        createDraggingElement(this, refElement, draggingHtml);
        this.component.ownerDocument.body.classList.add('dock-dragging');
    }
startDrag ( refElement , draggingHtml ) { if ( ! this . _init ) { throw new Error ( 'startDrag can only be used in onDragStart callback' ) ; } if ( refElement === undefined ) { refElement = this . component . element ; } createDraggingElement ( this , refElement , draggingHtml ) ; this . component . ownerDocument . body . classList . add ( 'dock-dragging' ) ; }
@param refElement, the element being moved
 @param draggingHtml, the element show in the dragging layer
@param refElement the element being moved @param draggingHtml the element show in the dragging layer