[novikov]

{
    viewConfig: {
		plugins: {
			ptype: 'gridviewdragdrop',
			dragText: 'Drag and drop to reorganize',
            dropZone : {
                onNodeOver : function (node, dd) {
                    var result = this.callParent(arguments);
                    
                    // we allow to drop to nodes having ID > 3
                    var record = dd.view.getRecord(node);
                    var isValid = record && record.getId() > 3;
                    
                    if (!isValid) {
                        return this.dropNotAllowed;
                    }

                    return result;
                }
            }
		}
	},
}

fiddle