diff --git a/rugnux/RugnuxDefaults.h b/rugnux/RugnuxDefaults.h
index 2f2442f03..a94b687eb 100644
--- a/rugnux/RugnuxDefaults.h
+++ b/rugnux/RugnuxDefaults.h
@@ -46,7 +46,7 @@ void ApplyRugnuxExperimentDefaults(DiffractionExperiment &experiment);
 // it to that lattice, and a stored space group skips the search outright. The CLI calls this and then
 // applies -C / -S (or a reference MTZ) on top; the viewer instead takes the crystal straight from its
 // settings panel, which clears both fields when "Unit cell known" is unticked - as it is when a file is
-// opened.
+// opened or a run's results are shown.
 void ClearStoredCrystal(DiffractionExperiment &experiment);
 
 // Scaling/merging defaults for the workflow. Several differ between rotation and stills because the
diff --git a/viewer/JFJochViewerWindow.cpp b/viewer/JFJochViewerWindow.cpp
index 2f85ebd3b..6fb7d2481 100644
--- a/viewer/JFJochViewerWindow.cpp
+++ b/viewer/JFJochViewerWindow.cpp
@@ -627,8 +627,11 @@ JFJochViewerWindow::JFJochViewerWindow(QWidget *parent, bool dbus, const QString
             reading_worker, &JFJochImageReadingWorker::FindCenter);
     connect(this, &JFJochViewerWindow::datasetReady,
             settingsPanel, &JFJochViewerSettingsDock::datasetLoaded);
+    // Both arrive after the datasetLoaded that fills the panel from the new file / run.
     connect(reading_worker, &JFJochImageReadingWorker::fileOpened,
-            settingsPanel, &JFJochViewerSettingsDock::fileOpened);
+            settingsPanel, &JFJochViewerSettingsDock::forgetStoredCrystal);
+    connect(reading_worker, &JFJochImageReadingWorker::snapshotsChanged,
+            settingsPanel, &JFJochViewerSettingsDock::forgetStoredCrystal);
     connect(this, &JFJochViewerWindow::imageReady,
             settingsPanel, &JFJochViewerSettingsDock::loadImage);
     connect(settingsPanel, &JFJochViewerSettingsDock::ringsFromCalibration,
diff --git a/viewer/widgets/JFJochViewerSettingsDock.cpp b/viewer/widgets/JFJochViewerSettingsDock.cpp
index 1a7dc456a..b953a1d5d 100644
--- a/viewer/widgets/JFJochViewerSettingsDock.cpp
+++ b/viewer/widgets/JFJochViewerSettingsDock.cpp
@@ -1022,7 +1022,7 @@ void JFJochViewerSettingsDock::datasetLoaded(std::shared_ptr<const JFJochReaderD
     ApplyProcessingMode();   // the mode just read back decides rotation vs stills
 }
 
-void JFJochViewerSettingsDock::fileOpened() {
+void JFJochViewerSettingsDock::forgetStoredCrystal() {
     cellKnown_->setChecked(false);   // a change emits the experiment without the crystal
 }
 
diff --git a/viewer/widgets/JFJochViewerSettingsDock.h b/viewer/widgets/JFJochViewerSettingsDock.h
index f6f9faf58..3bed5212f 100644
--- a/viewer/widgets/JFJochViewerSettingsDock.h
+++ b/viewer/widgets/JFJochViewerSettingsDock.h
@@ -42,9 +42,9 @@ public:
 
 public slots:
     void datasetLoaded(std::shared_ptr<const JFJochReaderDataset> dataset);
-    // A new file: the crystal it stores is shown but not used until "Known unit cell" is ticked, as a
-    // bare `rugnux` forgets it (ClearStoredCrystal).
-    void fileOpened();
+    // A new file, or a run's results shown: the crystal they store is shown but not used until "Known
+    // unit cell" is ticked, as a bare `rugnux` forgets it (ClearStoredCrystal).
+    void forgetStoredCrystal();
     void loadImage(std::shared_ptr<const JFJochReaderImage> image);
     void referenceLoaded(ReferenceMtzInfo info);   // worker reports a (un)loaded reference MTZ
     // Dataset re-processing reads a stored HDF5 file, so it is unavailable on a live HTTP stream:
diff --git a/viewer/windows/JFJochProcessingJobsWindow.cpp b/viewer/windows/JFJochProcessingJobsWindow.cpp
index 9ff12cdb2..0ba1ddbe4 100644
--- a/viewer/windows/JFJochProcessingJobsWindow.cpp
+++ b/viewer/windows/JFJochProcessingJobsWindow.cpp
@@ -432,10 +432,9 @@ void JFJochProcessingJobsWindow::newJob(ProcessMode mode, CalibrationSelection c
     //
     // The cell and space group come from the settings panel and nowhere else: with "Unit cell known"
     // ticked they are indexed and merged with, unticked the panel clears both and the run determines
-    // them from the data (-C / -S versus bare `rugnux`). A newly opened file starts unticked - its stored
-    // crystal is shown but not used, as `rugnux` forgets it - so what a run uses is always the crystal
-    // shown on screen. A finished job's _process.h5 becoming the active snapshot does tick it with the
-    // run's crystal (a run that ended in P1 shows P1), which can be cleared before the next run.
+    // them from the data (-C / -S versus bare `rugnux`). A newly opened file, and a run's results when
+    // they are shown, start unticked - the crystal they store is shown but not used, as `rugnux` forgets
+    // it - so what a run uses is always the crystal ticked on screen.
     DiffractionExperiment experiment = inputs.experiment;
     const auto polarization = experiment.GetPolarizationFactor();
     ApplyRugnuxExperimentDefaults(experiment);