Intermediate, fixes a lot of update problems, keeping selection in place when updating planets still broken.

Stars Assistant/Services/PlanetManager.cs

@@ -1,6 +1,9 @@
 using System;
 using System.ComponentModel;
+using System.Reactive;
+using System.Reactive.Disposables;
 using System.Reactive.Linq;
+using System.Reactive.Subjects;
 using DynamicData;
 using DynamicData.Binding;
 using Splat;
@@ -27,10 +30,21 @@ public class PlanetManager : IDisposable, IEnableLogger
                 .Filter(planet => planet.OwnerId == Game.Player.Name)
                 .Transform(planet => new PlayerPlanetViewModel(planet));
 
+    /// <summary>
+    /// Observable subject to trigger when we update the planet cache, allows the
+    /// UI to react to it.
+    /// </summary>
+    private readonly Subject<Unit> _planetsReloadedSubject = new();
+
+    /// <summary>
+    /// Exposes _planetReloadedSubject as IObservable.
+    /// </summary>
+    public IObservable<Unit> PlanetsReloaded => _planetsReloadedSubject.AsObservable();
+
+    
     public PlanetManager() 
     {
         FleetManager fleetManager = Locator.Current.GetService<FleetManager>()!;
-        
     }
 
     /// <summary>
@@ -50,6 +64,7 @@ public class PlanetManager : IDisposable, IEnableLogger
                 innerCache.AddOrUpdate(allPlanets);
             }
         );
+        _planetsReloadedSubject.OnNext(Unit.Default);
     }
 
     /// <summary>
@@ -60,6 +75,7 @@ public class PlanetManager : IDisposable, IEnableLogger
         if (disposing)
         {
             _planets.Dispose();
+            _planetsReloadedSubject.Dispose();
         }
     }
 

Stars Assistant/ViewModels/BuColViewModel.cs

@@ -15,23 +15,38 @@ public partial class BuColViewModel : ViewModelBase
     private readonly ReadOnlyObservableCollection<PlayerPlanetViewModel> _playerPlanetsView;
     public ReadOnlyObservableCollection<PlayerPlanetViewModel> PlayerPlanets => _playerPlanetsView;
 
+    [Reactive]
+    private PlayerPlanetViewModel? _selectedPlanet;
+
+    private string? _lastSelectedPlanetName;
+    
     public BuColViewModel()
     {
-        var PlanetManager = Locator.Current.GetService<PlanetManager>()!;
+        var planetManager = Locator.Current.GetService<PlanetManager>()!;
 
-        PlanetManager.PlayerPlanetsSource
+        planetManager.PlayerPlanetsSource
             .ObserveOn(RxApp.MainThreadScheduler)
             .Bind(out _playerPlanetsView)
             .DisposeMany()
             .Subscribe();
 
+        this.WhenAnyValue(x => x.SelectedPlanet)
+            .Subscribe(planet => _lastSelectedPlanetName = planet?.Name);
+        
         this.WhenActivated((CompositeDisposable disposables) => 
         {
-            // /* handle activation */
+            planetManager.PlanetsReloaded
-            // Disposable
+                .ObserveOn(RxApp.MainThreadScheduler)
-            //     .Create(() => { /* handle deactivation */ })
+                .Subscribe(_ => RestoreSelection())
-            //     .DisposeWith(disposables);
+                .DisposeWith(disposables);
         });
     }
 
+    private void RestoreSelection()
+    {
+        if (_lastSelectedPlanetName != null)
+        {
+            SelectedPlanet = PlayerPlanets.FirstOrDefault(p => p.Name == _lastSelectedPlanetName);
+        }
+    }
 }

Stars Assistant/ViewModels/PlayerPlanetViewModel.cs

@@ -67,6 +67,8 @@ public partial class PlayerPlanetViewModel : ViewModelBase
         _fleetSummaryChanges = fm.FleetSummariesByDestination
             .Connect()
             .Watch(Name)
+            .Replay(1)
+            .RefCount()
             .Log(this, "fleetSummaryChange", change => $"{Name}: {change.Reason}: {change.Previous} => {change.Current}")
         ;
 
@@ -94,8 +96,9 @@ public partial class PlayerPlanetViewModel : ViewModelBase
             .ToProperty(this, vm => vm.EnRouteGermanium)
         ;
         
-        this.WhenActivated((CompositeDisposable disposables) => 
+        this.WhenActivated((CompositeDisposable disposables) =>
         {
+            _fleetSummaryChanges.Subscribe().DisposeWith(disposables);
             disposables.Add(_enRoutePopulationHelper);
             disposables.Add(_enRouteIroniumHelper);
             disposables.Add(_enRouteBoraniumHelper);

Stars Assistant/Views/BuColView.axaml

@@ -10,11 +10,12 @@
 
   <DataGrid x:Name="PlanetsGrid"
     ItemsSource="{Binding PlayerPlanets}"
+    SelectedItem="{Binding SelectedPlanet}"
     GridLinesVisibility="All"
     FrozenColumnCount="1"
-    
     BorderThickness="1" BorderBrush="Gray">
-    <DataGrid.Columns>
+      
+      <DataGrid.Columns>
         <DataGridTextColumn Header="Planet" Binding="{Binding Name}" />
         <!-- Class -->
         <!-- Info -->