Fix min max issues in statistics chart (#28493)

src/components/chart/statistics-chart.ts

@@ -184,17 +184,11 @@ export class StatisticsChart extends LitElement {
   }
 
   private _datasetHidden(ev: CustomEvent) {
-    if (!this._legendData) {
-      return;
-    }
     this._hiddenStats.add(ev.detail.id);
     this.requestUpdate("_hiddenStats");
   }
 
   private _datasetUnhidden(ev: CustomEvent) {
-    if (!this._legendData) {
-      return;
-    }
     this._hiddenStats.delete(ev.detail.id);
     this.requestUpdate("_hiddenStats");
   }
@@ -521,7 +515,9 @@ export class StatisticsChart extends LitElement {
                   `ui.components.statistics_charts.statistic_types.${type}`
                 ),
             symbol: "none",
-            sampling: "minmax",
+            // minmax sampling operates independently per series, breaking stacking alignment
+            // https://github.com/apache/echarts/issues/11879
+            sampling: band && drawBands ? "lttb" : "minmax",
             animationDurationUpdate: 0,
             lineStyle: {
               width: 1.5,
@@ -539,12 +535,19 @@ export class StatisticsChart extends LitElement {
           if (band && this.chartType === "line") {
             series.stack = `band-${statistic_id}`;
             series.stackStrategy = "all";
+            if (this._hiddenStats.has(`${statistic_id}-${bandBottom}`)) {
+              // changing the stackOrder forces echarts to render the stacked series that are not hidden #28472
+              series.stackOrder = "seriesDesc";
+              (series as LineSeriesOption).areaStyle = undefined;
+            } else {
+              series.stackOrder = "seriesAsc";
               if (drawBands && type === bandTop) {
                 (series as LineSeriesOption).areaStyle = {
                   color: color + "3F",
                 };
               }
             }
+          }
           if (!this.hideLegend) {
             const showLegend = hasMean
               ? type === "mean"
@@ -586,7 +589,8 @@ export class StatisticsChart extends LitElement {
           } else if (
             type === bandTop &&
             this.chartType === "line" &&
-            drawBands
+            drawBands &&
+            !this._hiddenStats.has(`${statistic_id}-${bandBottom}`)
           ) {
             const top = stat[bandTop] || 0;
             val.push(Math.abs(top - (stat[bandBottom] || 0)));