declare namespace Ext {
    export namespace chart {
        export namespace interactions {
            export interface ItemHighlightConfig {
                chart?: Ext.chart.AbstractChart;
                enabled?: boolean;
                listeners?: object;
                sticky?: boolean;
            }

            export class ItemHighlight extends Ext.chart.interactions.Abstract  {
                public getSticky(): void;
                public setSticky(): void;
            }
        }
    }
}