From 8b9bc9a9193c4743a7bbc22f2313aef8546f5356 Mon Sep 17 00:00:00 2001
From: Leon Sorokin <leeoniya@gmail.com>
Date: Wed, 6 Mar 2024 12:50:28 -0600
Subject: [PATCH] Histogram: Fix 'combine' option & legend rendering (#84026)

---
 .../src/transformations/transformers/histogram.ts          | 7 ++++++-
 public/app/plugins/panel/histogram/Histogram.tsx           | 4 +++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/packages/grafana-data/src/transformations/transformers/histogram.ts b/packages/grafana-data/src/transformations/transformers/histogram.ts
index ea5ea3c9770..39d54ffeda9 100644
--- a/packages/grafana-data/src/transformations/transformers/histogram.ts
+++ b/packages/grafana-data/src/transformations/transformers/histogram.ts
@@ -482,7 +482,12 @@ export function buildHistogram(frames: DataFrame[], options?: HistogramTransform
         name: 'count',
         values: vals,
         type: FieldType.number,
-        state: undefined,
+        state: {
+          ...counts[0].state,
+          displayName: 'Count',
+          multipleFrames: false,
+          origin: { frameIndex: 0, fieldIndex: 2 },
+        },
       },
     ];
   } else {
diff --git a/public/app/plugins/panel/histogram/Histogram.tsx b/public/app/plugins/panel/histogram/Histogram.tsx
index a2bb2ae2783..160db11fe36 100644
--- a/public/app/plugins/panel/histogram/Histogram.tsx
+++ b/public/app/plugins/panel/histogram/Histogram.tsx
@@ -312,7 +312,9 @@ export class Histogram extends React.Component<HistogramProps, State> {
       return null;
     }
 
-    return <PlotLegend data={this.props.rawSeries!} config={config} maxHeight="35%" maxWidth="60%" {...legend} />;
+    const frames = this.props.options.combine ? [this.props.alignedFrame] : this.props.rawSeries!;
+
+    return <PlotLegend data={frames} config={config} maxHeight="35%" maxWidth="60%" {...legend} />;
   }
 
   componentDidUpdate(prevProps: HistogramProps) {