fix: the EDS results header and exports name the kept region

Sources/ShellEDXModel/EDXSession.swift

@@ -244,13 +244,17 @@ public final class EDXSession {
     public var beamEnergy: Double? { method.beamEnergyKeV ?? fileBeamEnergy }
     /// A one-pixel file (an .msa, a single Velox spectrum): there are no maps, no region to draw, and the words say "Spectrum", not "Whole map".
     public var isSingleSpectrum: Bool { (source?.nx ?? 0) * (source?.ny ?? 0) == 1 }
-    public var regionName: String { isSingleSpectrum ? "Spectrum" : region.name }
+    /// The selected region's name as the person reads it: the kept region's own ("Region 2", or what it was renamed to), "Region" for a
+    /// shape not kept, "Whole map", or "Spectrum" for a one-pixel file. The results header, the export names and the CSVs' region lines.
+    public var regionName: String { isSingleSpectrum ? "Spectrum" : keptName }
+    /// The kept region's name, else the region's ("Region", "Whole map").
+    private var keptName: String { selectedPin?.name ?? region.name }
     public var canQuantify: Bool { hasImage && picks.contains { $0.role == .quantify } }
     public var quantifyBlocker: String? {
         hasImage && !canQuantify ? "Pick at least one element to quantify." : nil
     }
     /// The default stem of an export file: the image, the region.
-    public var exportStem: String { SpectroscopyExport.fileStem(imageName: fileName, regionName: region.name) }
+    public var exportStem: String { SpectroscopyExport.fileStem(imageName: fileName, regionName: keptName) }
 
     // MARK: Opening
 
@@ -735,7 +739,7 @@ public final class EDXSession {
         }
         autoID = .running
         let region = region, cache = cache, listed = picks.map(\.symbol), computedK = method.kFactorSource == .computed
-        let regionName = region.name
+        let regionName = keptName
         autoIDRun += 1
         let run = autoIDRun
         let task = Task.detached(priority: .userInitiated) { [weak self] in
@@ -1058,16 +1062,16 @@ public final class EDXSession {
 
     // MARK: Export
 
-    public var resultsCSV: String? { fit.map { EDXCompute.resultsCSV($0, regionName: region.name, host: host) } }
+    public var resultsCSV: String? { fit.map { EDXCompute.resultsCSV($0, regionName: keptName, host: host) } }
     public var methodJSON: String? { fit.map { SpectroscopyExport.methodJSON($0.method) } }
     /// The region's spectrum as an `.msa` file (FormatoKit's writer); nil before there is a spectrum.
     public func spectrumMSA() throws -> Data? {
         guard let source, !spectrumCounts.isEmpty else { return nil }
-        return try EDXExports.msa(counts: spectrumCounts, axis: source.energyAxis, title: "\(fileName) \(region.name)", beamEnergyKeV: beamEnergy, host: host)
+        return try EDXExports.msa(counts: spectrumCounts, axis: source.energyAxis, title: "\(fileName) \(keptName)", beamEnergyKeV: beamEnergy, host: host)
     }
     public var spectrumCSV: String? {
         guard let source, !spectrumCounts.isEmpty else { return nil }
-        return EDXCompute.spectrumCSV(counts: spectrumCounts, axis: source.energyAxis, fileName: fileName, regionName: region.name, host: host)
+        return EDXCompute.spectrumCSV(counts: spectrumCounts, axis: source.energyAxis, fileName: fileName, regionName: keptName, host: host)
     }
 }
 

Tests/ShellEDXTests/EDXRegionsTests.swift

@@ -31,6 +31,26 @@ nonisolated final class EDXRegionsTests: XCTestCase {
 
     // MARK: Several regions
 
+    /// The results header, the export stem and the CSVs name the kept region by its own name, so two regions' exports do not overwrite each other
+    /// (seen 2026-11-05 on the owner's 1339 file: "Results · Region" and "…_Region quantification.csv" for Region 1 and Region 2 alike). (A shape selected but not kept
+    /// stays "Region": testShapesCoveringTheSamePixelsSumTheSameSpectrum.) Red under: `region.name` (always "Region" for a shape) in the header and the export names.
+    @MainActor func testTheHeaderAndTheExportsNameTheKeptRegion() async throws {
+        let session = await openRoom()
+        session.drawRectangle(PixelRect(x0: 0, y0: 0, x1: 1, y1: 1))
+        session.drawRectangle(PixelRect(x0: 1, y0: 0, x1: 2, y1: 1))
+        await session.settled()
+        XCTAssertEqual(session.regionName, "Region 2")
+        XCTAssertTrue(session.exportStem.hasSuffix("Region_2") || session.exportStem.hasSuffix("Region 2"), session.exportStem)
+        let two = session.exportStem
+        session.selectPin(session.pins[0].id)
+        await session.settled()
+        XCTAssertEqual(session.regionName, "Region 1")
+        XCTAssertNotEqual(session.exportStem, two, "the two regions' exports share a name")
+        XCTAssertTrue(try XCTUnwrap(session.spectrumCSV).contains("region: Region 1"))
+        session.renamePin(session.pins[0].id, to: "Precipitate")
+        XCTAssertEqual(session.regionName, "Precipitate")
+    }
+
     /// Every shape drawn is kept as the next numbered region: two drawn shapes are two regions, each with its own pooled spectrum (the kit's sum of its pixels,
     /// exact), a table row with its pixel count and counts, and hiding one drops its layer but keeps its row. A shape drawn twice is one region; a deleted
     /// region's number is not reused. Red under: a second drawing replacing the first; the layer of a hidden region kept; numbers recycled.