Fixes microsoft#208615

Author: hediet

src/vs/editor/browser/widget/diffEditor/features/gutterFeature.ts

@@ -84,7 +84,7 @@ export class DiffEditorGutter extends Disposable {
 				const currentDiff = this._currentDiff.read(reader);
 
 				return diffs.mappings.map(m => new DiffGutterItem(
-					m.lineRangeMapping,
+					m.lineRangeMapping.withInnerChangesFromLineRanges(),
 					m.lineRangeMapping === currentDiff?.lineRangeMapping,
 					MenuId.DiffEditorHunkToolbar,
 					undefined,

src/vs/editor/common/diff/rangeMapping.ts

@@ -118,6 +118,12 @@ export class DetailedLineRangeMapping extends LineRangeMapping {
 	public override flip(): DetailedLineRangeMapping {
 		return new DetailedLineRangeMapping(this.modified, this.original, this.innerChanges?.map(c => c.flip()));
 	}
+
+	public withInnerChangesFromLineRanges(): DetailedLineRangeMapping {
+		return new DetailedLineRangeMapping(this.original, this.modified, [
+			new RangeMapping(this.original.toExclusiveRange(), this.modified.toExclusiveRange()),
+		]);
+	}
 }
 
 /**