Fix extinct species not having preview in auto-evo exporer

src/auto-evo/AutoEvoExploringTool.cs

@@ -385,10 +385,15 @@ public void AskExit()
     }
 
     public Species? GetActiveSpeciesData(uint speciesId)
+    {
+        return GetActiveSpeciesDataFromGeneration(generationDisplayed, speciesId);
+    }
+
+    public Species? GetActiveSpeciesDataFromGeneration(int generation, uint speciesId)
     {
         var gameWorld = world.GameProperties.GameWorld;
 
-        for (int i = generationDisplayed; i >= 0; --i)
+        for (int i = generation; i >= 0; --i)
         {
             gameWorld.GenerationHistory[i].AllSpeciesData
                 .TryGetValue(speciesId, out var speciesRecord);
@@ -882,16 +887,31 @@ private void SpeciesListMenuIndexChanged(int index)
         UpdateSpeciesPreview(species);
     }
 
-    private void UpdateSpeciesPreview(Species species)
+    private void UpdateSpeciesPreview(Species? species)
     {
+        if (species == null)
+        {
+            ResetSpeciesPreview();
+            return;
+        }
+
         speciesListMenu.Text = species.FormattedName;
         speciesDetailsPanelWithFossilisation.PreviewSpecies = species;
     }
 
+    private void ResetSpeciesPreview()
+    {
+        speciesListMenu.Text = string.Empty;
+        speciesDetailsPanelWithFossilisation.PreviewSpecies = null;
+    }
+
     private void EvolutionaryTreeNodeSelected(int generation, uint id)
     {
         HistoryListMenuIndexChanged(generation);
-        UpdateSpeciesPreview(world.SpeciesHistoryList[generation][id]);
+
+        var species = GetActiveSpeciesDataFromGeneration(generation, id);
+
+        UpdateSpeciesPreview(species);
     }
 
     private void PatchListMenuIndexChanged(int index)

src/gui_common/PhotographablePreview.cs

@@ -101,6 +101,11 @@ protected void UpdatePreview()
         task = SetupImageTask();
     }
 
+    protected void ResetPreview()
+    {
+        textureRect.Texture = null!;
+    }
+
     /// <summary>
     ///   Return an ImageTask ready for PhotoStudio to process
     /// </summary>

src/gui_common/SpeciesDetailsPanel.cs

@@ -32,7 +32,7 @@ public Species? PreviewSpecies
 
             previewSpecies = value;
 
-            if (previewSpecies != null && speciesDetailsLabel != null)
+            if (speciesDetailsLabel != null)
                 UpdateSpeciesPreview();
         }
     }
@@ -83,7 +83,11 @@ private void UpdateSpeciesPreview()
     {
         speciesPreview.PreviewSpecies = PreviewSpecies;
 
-        if (PreviewSpecies is MicrobeSpecies microbeSpecies)
+        if (PreviewSpecies == null)
+        {
+            hexesPreview.PreviewSpecies = null;
+        }
+        else if (PreviewSpecies is MicrobeSpecies microbeSpecies)
         {
             hexesPreview.PreviewSpecies = microbeSpecies;
         }

src/gui_common/SpeciesDetailsPanelWithFossilisation.cs

@@ -81,6 +81,6 @@ private void OnFossilisePressed()
 
     private void UpdateFossilisationButtonState()
     {
-        fossilisationButton.Disabled = previewSpecies is not MicrobeSpecies;
+        fossilisationButton.Disabled = previewSpecies is null or not MicrobeSpecies;
     }
 }

src/gui_common/SpeciesPreview.cs

@@ -19,6 +19,8 @@ public Species? PreviewSpecies
 
             if (previewSpecies != null)
                 UpdatePreview();
+            else
+                ResetPreview();
         }
     }
 

src/microbe_stage/CellHexesPreview.cs

@@ -17,7 +17,11 @@ public MicrobeSpecies? PreviewSpecies
                 return;
 
             microbeSpecies = value;
-            UpdatePreview();
+
+            if (microbeSpecies != null)
+                UpdatePreview();
+            else
+                ResetPreview();
         }
     }
 

src/thriveopedia/ThriveopediaManager.cs

@@ -54,8 +54,7 @@ public static IThriveopediaPage GetPage(string pageName)
         {
             var species = provider.GetActiveSpeciesData(speciesId);
 
-            if (species != null)
-                return species;
+            return species;
         }
 
         return null;