declare namespace Ext {
    export namespace grid {
        export namespace feature {
            export interface GroupingSummaryConfig {
                collapsible?: boolean;
                depthToIndent?: number;
                enableGroupingMenu?: boolean;
                enableNoGroups?: boolean;
                groupByText?: string;
                groupers?: [];
                groupHeaderTpl?: string | Ext.Template | [];
                hideGroupedHeader?: boolean;
                listeners?: object;
                remoteRoot?: string;
                showGroupsText?: string;
                showSummaryRow?: boolean;
                startCollapsed?: boolean;
            }

            export class GroupingSummary extends Ext.grid.feature.Grouping  {
            }
        }
    }
}