diff --git a/PriceChecker.Core/Services/PriceSeeker.cs b/PriceChecker.Core/Services/PriceSeeker.cs
index 4471828..87ea2ea 100644
--- a/PriceChecker.Core/Services/PriceSeeker.cs
+++ b/PriceChecker.Core/Services/PriceSeeker.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Linq;
 using System.Text.RegularExpressions;
 using System.Threading;
@@ -37,14 +38,23 @@ public async Task<PriceSeekResult[]> SeekAsync(Product product, CancellationToke
             });
 
             return await Task.WhenAll(result)
-                .ContinueWith(x => x.Result?.Where(x => x != null).ToArray() ?? new PriceSeekResult[0]);
+                .ContinueWith(x => x.Result?.Where(x => x != null).ToArray() ?? new PriceSeekResult[0], TaskContinuationOptions.OnlyOnRanToCompletion);
         }
 
         private async Task<PriceSeekResult> Seek(ProductSource productSource, CancellationToken cancel)
         {
             var agent = productSource.Agent;
             var url = string.Format(agent.Url, productSource.AgentArgument);
-            var content = await _trickyHttpClient.DownloadContent(url, cancel);
+            string content;
+            try
+            {
+                content = await _trickyHttpClient.DownloadContent(url, cancel);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, $"Failed loading content for source `{productSource.AgentId}`, url = `{url}`");
+                throw;
+            }
             if (content == null)
                 return null;
 
diff --git a/PriceChecker.Infrastructure/Events/EventBus.cs b/PriceChecker.Infrastructure/Events/EventBus.cs
index 74d0ee9..ff3b5aa 100644
--- a/PriceChecker.Infrastructure/Events/EventBus.cs
+++ b/PriceChecker.Infrastructure/Events/EventBus.cs
@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Concurrent;
 using System.Reactive;
 using System.Reactive.Linq;
 
diff --git a/PriceChecker.UI.Forms/AutoGrid/AttachingBehavior.cs b/PriceChecker.UI.Forms/AutoGrid/AttachingBehavior.cs
index c5ccf5f..7d81e86 100644
--- a/PriceChecker.UI.Forms/AutoGrid/AttachingBehavior.cs
+++ b/PriceChecker.UI.Forms/AutoGrid/AttachingBehavior.cs
@@ -57,7 +57,7 @@ private void OnItemsSourceChanged(object sender, EventArgs e)
             }
 
             if (AssociatedObject.SelectionMode == DataGridSelectionMode.Extended &&
-                typeof(ISelectable).IsAssignableFrom(GetItemType()))
+                typeof(ISelectable).IsAssignableFrom(Helpers.GetListItemType(AssociatedObject.ItemsSource)))
             {
                 BindIsSelected();
             }
@@ -118,15 +118,5 @@ private void BindIsSelected()
             rowStyle.Setters.Add(new Setter(DataGrid.IsSelectedProperty, binding));
             AssociatedObject.RowStyle = rowStyle;
         }
-
-        private Type GetItemType()
-        {
-            var sourceCollection = AssociatedObject.ItemsSource;
-            if (sourceCollection is ListCollectionView listCollectionView)
-            {
-                sourceCollection = listCollectionView.SourceCollection;
-            }
-            return sourceCollection.GetType().GetGenericArguments().Single();
-        }
     }
 }
diff --git a/PriceChecker.UI.Forms/AutoGrid/Properties.cs b/PriceChecker.UI.Forms/AutoGrid/Properties.cs
index f1e4014..03c9254 100644
--- a/PriceChecker.UI.Forms/AutoGrid/Properties.cs
+++ b/PriceChecker.UI.Forms/AutoGrid/Properties.cs
@@ -30,9 +30,9 @@ public static IEnumerable GetItemsSource(DependencyObject element)
             return (IEnumerable) element.GetValue(ItemsSourceProperty);
         }
 
-        public static void ItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        private static void ItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
-            var itemType = e.NewValue.GetType().GetGenericArguments().Single();
+            var itemType = Helpers.GetListItemType(e.NewValue);
             var properties = itemType.GetProperties();
             var groupByProps = properties
                 .Where(x => x.GetCustomAttributes(false).OfType<GroupByAttribute>().Any())
diff --git a/PriceChecker.UI.Forms/Helpers.cs b/PriceChecker.UI.Forms/Helpers.cs
new file mode 100644
index 0000000..28ab6c2
--- /dev/null
+++ b/PriceChecker.UI.Forms/Helpers.cs
@@ -0,0 +1,26 @@
+using System;
+using System.Linq;
+using System.Text.RegularExpressions;
+using System.Windows.Data;
+
+namespace Genius.PriceChecker.UI.Forms
+{
+    internal class Helpers
+    {
+        public static Type GetListItemType(object value)
+        {
+            if (value is ListCollectionView listCollectionView)
+                value = listCollectionView.SourceCollection;
+
+            if (value is ITypedObservableList typedObservableList)
+                return typedObservableList.ItemType;
+
+            return value.GetType().GetGenericArguments().Single();
+        }
+
+        public static string MakeCaptionFromPropertyName(string propertyName)
+        {
+            return Regex.Replace(propertyName, @"(?<=[^$])([A-Z])", " $1");
+        }
+    }
+}
diff --git a/PriceChecker.UI.Forms/TypedObservableList.cs b/PriceChecker.UI.Forms/TypedObservableList.cs
new file mode 100644
index 0000000..bae92d7
--- /dev/null
+++ b/PriceChecker.UI.Forms/TypedObservableList.cs
@@ -0,0 +1,26 @@
+using System;
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+
+namespace Genius.PriceChecker.UI.Forms
+{
+    public interface ITypedObservableList
+    {
+        Type ItemType { get; }
+    }
+
+    public class TypedObservableList<TContract, TType> : ObservableCollection<TContract>, ITypedObservableList, ITypedList
+    {
+        public PropertyDescriptorCollection GetItemProperties(PropertyDescriptor[] listAccessors)
+        {
+            return TypeDescriptor.GetProperties(typeof(TType));
+        }
+
+        public string GetListName(PropertyDescriptor[] listAccessors)
+        {
+            return null;
+        }
+
+        public Type ItemType => typeof(TType);
+    }
+}
diff --git a/PriceChecker.UI.Forms/ViewModels/TabViewModelBase.cs b/PriceChecker.UI.Forms/ViewModels/TabViewModelBase.cs
index 54fb122..02a4c01 100644
--- a/PriceChecker.UI.Forms/ViewModels/TabViewModelBase.cs
+++ b/PriceChecker.UI.Forms/ViewModels/TabViewModelBase.cs
@@ -2,7 +2,7 @@
 
 namespace Genius.PriceChecker.UI.Forms.ViewModels
 {
-    public interface ITabViewModel
+    public interface ITabViewModel : IViewModel
     {
         IActionCommand Activated { get; }
         IActionCommand Deactivated { get; }
diff --git a/PriceChecker.UI.Forms/ViewModels/ViewModelBase.cs b/PriceChecker.UI.Forms/ViewModels/ViewModelBase.cs
index 866c988..6d57d12 100644
--- a/PriceChecker.UI.Forms/ViewModels/ViewModelBase.cs
+++ b/PriceChecker.UI.Forms/ViewModels/ViewModelBase.cs
@@ -12,13 +12,17 @@
 
 namespace Genius.PriceChecker.UI.Forms.ViewModels
 {
-    public abstract class ViewModelBase : INotifyPropertyChanged, INotifyDataErrorInfo
+  public interface IViewModel : INotifyPropertyChanged, INotifyDataErrorInfo
+    {
+        bool TryGetPropertyValue(string propertyName, out object value);
+    }
+
+    public abstract class ViewModelBase : IViewModel
     {
         protected readonly ConcurrentDictionary<string, object> _propertyBag = new();
         private readonly Dictionary<string, List<ValidationRule>> _validationRules = new();
         private readonly Dictionary<string, List<string>> _errors = new();
-
-        protected bool PropertiesAreInitialized = false;
+        private bool _suspendDirtySet = false;
 
         public ViewModelBase()
         {
@@ -34,11 +38,29 @@ public IEnumerable GetErrors(string propertyName)
                 new List<string>();
         }
 
-        internal bool TryGetPropertyValue(string propertyName, out object value)
+        public bool TryGetPropertyValue(string propertyName, out object value)
         {
             return _propertyBag.TryGetValue(propertyName, out value);
         }
 
+        protected void InitializeProperties(Action action)
+        {
+            _suspendDirtySet = true;
+            try
+            {
+                action();
+
+                if (this is IHasDirtyFlag hasDirtyFlag)
+                {
+                    hasDirtyFlag.IsDirty = false;
+                }
+            }
+            finally
+            {
+                _suspendDirtySet = false;
+            }
+        }
+
         protected T GetOrDefault<T>(T defaultValue = default(T), [CallerMemberName] string name = null)
         {
             if (name == null)
@@ -74,9 +96,9 @@ protected void RaiseAndSetIfChanged<T>(T value, Action<T, T> valueChangedHandler
             _propertyBag.AddOrUpdate(name, _ => value, (_, __) => value);
             OnPropertyChanged(name);
 
-            if (this is IHasDirtyFlag hasDirtyFlag &&
+            if (!_suspendDirtySet &&
+                this is IHasDirtyFlag hasDirtyFlag &&
                 name != nameof(IHasDirtyFlag.IsDirty) &&
-                PropertiesAreInitialized &&
                 (this is not ISelectable || name != nameof(ISelectable.IsSelected)))
             {
                 hasDirtyFlag.IsDirty = true;
diff --git a/PriceChecker.UI.Forms/ViewModels/ViewModelExtensions.cs b/PriceChecker.UI.Forms/ViewModels/ViewModelExtensions.cs
index a7bcbe7..72d4833 100644
--- a/PriceChecker.UI.Forms/ViewModels/ViewModelExtensions.cs
+++ b/PriceChecker.UI.Forms/ViewModels/ViewModelExtensions.cs
@@ -8,14 +8,14 @@ namespace Genius.PriceChecker.UI.Forms.ViewModels
     public static class ViewModelExtensions
     {
         public static IDisposable WhenChanged<TViewModel, TProperty>(this TViewModel viewModel, Expression<Func<TViewModel, TProperty>> propertyAccessor, Action<TProperty> handler)
-            where TViewModel : ViewModelBase
+            where TViewModel : IViewModel
         {
             var propName = ExpressionHelpers.GetPropertyName(propertyAccessor);
 
             return WhenChanged(viewModel, propName, handler);
         }
 
-        public static IDisposable WhenChanged<TProperty>(this ViewModelBase viewModel, string propertyName, Action<TProperty> handler)
+        public static IDisposable WhenChanged<TProperty>(this IViewModel viewModel, string propertyName, Action<TProperty> handler)
         {
             PropertyChangedEventHandler fn = (_, args) =>
             {
diff --git a/PriceChecker.UI.Forms/WpfHelpers.cs b/PriceChecker.UI.Forms/WpfHelpers.cs
index 01674d8..5a56cea 100644
--- a/PriceChecker.UI.Forms/WpfHelpers.cs
+++ b/PriceChecker.UI.Forms/WpfHelpers.cs
@@ -34,7 +34,7 @@ public static void AddFlyout<T>(FrameworkElement owner, string isOpenBindingPath
 
         public static DataGridTemplateColumn CreateButtonColumn(string commandPath, string iconName)
         {
-            var caption = commandPath.Replace("Command", "");
+            var caption = Helpers.MakeCaptionFromPropertyName(commandPath.Replace("Command", ""));
 
             var buttonFactory = new FrameworkElementFactory(typeof(Button));
             buttonFactory.SetBinding(Button.CommandProperty, new Binding(commandPath));
diff --git a/PriceChecker.UI.Tests/Helpers/TrackerScanContextTests.cs b/PriceChecker.UI.Tests/Helpers/TrackerScanContextTests.cs
new file mode 100644
index 0000000..2c9ac76
--- /dev/null
+++ b/PriceChecker.UI.Tests/Helpers/TrackerScanContextTests.cs
@@ -0,0 +1,137 @@
+using System;
+using System.Reactive.Subjects;
+using AutoFixture;
+using Genius.PriceChecker.Core.Messages;
+using Genius.PriceChecker.Core.Models;
+using Genius.PriceChecker.UI.Helpers;
+using Xunit;
+
+namespace Genius.PriceChecker.UI.Tests.Helpers
+{
+  public class TrackerScanContextTests : TestBase
+    {
+        private readonly Fixture _fixture = new();
+        private readonly TrackerScanContext _sut;
+
+        // Session values:
+        private readonly Subject<ProductAutoScanStartedEvent> _productAutoScanStartedEventSubject;
+        private TrackerScanStatus? _lastStatus = null;
+        private double? _lastProgress = null;
+
+        public TrackerScanContextTests()
+        {
+            _productAutoScanStartedEventSubject = CreateEventSubject<ProductAutoScanStartedEvent>();
+
+            _sut = new TrackerScanContext(EventBusMock.Object);
+
+            _sut.ScanProgress.Subscribe(x => {
+                _lastStatus = x.Status;
+                _lastProgress = x.Progress;
+            });
+        }
+
+        [Fact]
+        public void NotifyStarted__Resets_state_and_calculates_initial_progress()
+        {
+            // Arrange
+            var count = 10;
+
+            // Act
+            _sut.NotifyStarted(count);
+
+            // Verify
+            var expectedProgress = 1d / (count * 2);
+            Assert.True(_sut.IsStarted);
+            Assert.False(_sut.HasErrors);
+            Assert.False(_sut.HasNewLowestPrice);
+            Assert.Equal(0, _sut.FinishedJobs);
+            Assert.Equal(TrackerScanStatus.InProgress, _lastStatus);
+            Assert.Equal(expectedProgress, _lastProgress);
+        }
+
+        [Fact]
+        public void NotifyProgressChange__When_ScannedOk__Increases_progress()
+        {
+            // Arrange
+            var count = 2;
+            _sut.NotifyStarted(count);
+
+            // Act
+            _sut.NotifyProgressChange(ProductScanStatus.ScannedOk);
+
+            // Verify
+            var expectedProgress = 0.5d; // 50% of 2 jobs
+            Assert.True(_sut.IsStarted);
+            Assert.False(_sut.HasErrors);
+            Assert.False(_sut.HasNewLowestPrice);
+            Assert.Equal(1, _sut.FinishedJobs);
+            Assert.Equal(TrackerScanStatus.InProgress, _lastStatus);
+            Assert.Equal(expectedProgress, _lastProgress);
+        }
+
+        [Fact]
+        public void NotifyProgressChange__When_scanned_last_job__Finishes_progress()
+        {
+            // Arrange
+            _sut.NotifyStarted(2);
+
+            // Act
+            _sut.NotifyProgressChange(ProductScanStatus.ScannedOk);
+            _sut.NotifyProgressChange(ProductScanStatus.ScannedOk);
+
+            // Verify
+            Assert.False(_sut.IsStarted);
+            Assert.False(_sut.HasErrors);
+            Assert.False(_sut.HasNewLowestPrice);
+            Assert.Equal(2, _sut.FinishedJobs);
+            Assert.Equal(TrackerScanStatus.Finished, _lastStatus);
+            Assert.Equal(1, _lastProgress);
+        }
+
+        [Fact]
+        public void NotifyProgressChange__When_ScannedWithErrors__Reports_about_errors()
+        {
+            // Arrange
+            _sut.NotifyStarted(_fixture.Create<int>());
+
+            // Act
+            _sut.NotifyProgressChange(ProductScanStatus.ScannedWithErrors);
+
+            // Verify
+            Assert.True(_sut.HasErrors);
+            Assert.Equal(TrackerScanStatus.InProgressWithErrors, _lastStatus);
+        }
+
+        [Fact]
+        public void NotifyProgressChange__When_ScannedNewLowest__Reports_about_new_lowest()
+        {
+            // Arrange
+            _sut.NotifyStarted(_fixture.Create<int>());
+
+            // Act
+            _sut.NotifyProgressChange(ProductScanStatus.ScannedNewLowest);
+
+            // Verify
+            Assert.True(_sut.HasNewLowestPrice);
+        }
+
+        [Fact]
+        public void ProductAutoScanStartedEvent_fired__Calls_NotifyStarted()
+        {
+            // Arrange
+            var count = 10;
+
+            // Act
+            _productAutoScanStartedEventSubject.OnNext(new ProductAutoScanStartedEvent(count));
+
+            // Verify
+            var expectedProgress = 1d / (count * 2);
+            Assert.True(_sut.IsStarted);
+            Assert.False(_sut.HasErrors);
+            Assert.False(_sut.HasNewLowestPrice);
+            Assert.Equal(0, _sut.FinishedJobs);
+            Assert.Equal(TrackerScanStatus.InProgress, _lastStatus);
+            Assert.Equal(expectedProgress, _lastProgress);
+        }
+    }
+}
diff --git a/PriceChecker.UI.Tests/TestBase.cs b/PriceChecker.UI.Tests/TestBase.cs
new file mode 100644
index 0000000..98325c6
--- /dev/null
+++ b/PriceChecker.UI.Tests/TestBase.cs
@@ -0,0 +1,58 @@
+using System;
+using System.ComponentModel;
+using System.Linq.Expressions;
+using System.Reactive.Subjects;
+using System.Windows.Threading;
+using AutoFixture;
+using Genius.PriceChecker.Infrastructure;
+using Genius.PriceChecker.Infrastructure.Events;
+using Genius.PriceChecker.UI.Forms.ViewModels;
+using Moq;
+
+namespace Genius.PriceChecker.UI.Tests
+{
+    public abstract class TestBase
+    {
+        public TestBase()
+        {
+            Fixture.Behaviors.Add(new OmitOnRecursionBehavior(recursionDepth: 2));
+
+            SetupDispatcher();
+        }
+
+        protected Subject<T> CreateEventSubject<T>()
+            where T : IEventMessage
+        {
+            Subject<T> subject = new();
+            EventBusMock.Setup(x => x.WhenFired<T>())
+                .Returns(subject);
+            return subject;
+        }
+
+        protected void RaisePropertyChanged<T>(Mock<T> container, Expression<Func<T, object>> propertyNameExpr, object value)
+            where T : class, IViewModel
+        {
+            var propertyName = ExpressionHelpers.GetPropertyName(propertyNameExpr);
+
+            container.Setup(x => x.TryGetPropertyValue(propertyName, out value))
+                .Returns(true);
+
+            container.Raise(x => x.PropertyChanged += null,
+                new PropertyChangedEventArgs(propertyName));
+        }
+
+        private static void SetupDispatcher()
+        {
+            var frame = new DispatcherFrame();
+            Dispatcher.CurrentDispatcher.BeginInvoke(
+                DispatcherPriority.Background,
+                new Action(() => frame.Continue = false));
+            Dispatcher.PushFrame(frame);
+        }
+
+        protected Fixture Fixture { get; } = new();
+
+        private Lazy<Mock<IEventBus>> _eventBusMock = new Lazy<Mock<IEventBus>>(() => new Mock<IEventBus>());
+        protected Mock<IEventBus> EventBusMock => _eventBusMock.Value;
+    }
+}
\ No newline at end of file
diff --git a/PriceChecker.UI.Tests/Validation/MustBeUniqueValidationRuleTests.cs b/PriceChecker.UI.Tests/Validation/MustBeUniqueValidationRuleTests.cs
index 0ccd93d..4ce18e6 100644
--- a/PriceChecker.UI.Tests/Validation/MustBeUniqueValidationRuleTests.cs
+++ b/PriceChecker.UI.Tests/Validation/MustBeUniqueValidationRuleTests.cs
@@ -20,7 +20,7 @@ public MustBeUniqueValidationRuleTests()
         }
 
         [Fact]
-        public void Value_not_string__Returns_valid()
+        public void Value__Not_string__Returns_valid()
         {
             // Act
             var result = _sut.Validate(new object(), _fixture.Create<CultureInfo>());
diff --git a/PriceChecker.UI.Tests/Validation/ValueCannotBeEmptyValidationRuleTests.cs b/PriceChecker.UI.Tests/Validation/ValueCannotBeEmptyValidationRuleTests.cs
index 8742812..51e171e 100644
--- a/PriceChecker.UI.Tests/Validation/ValueCannotBeEmptyValidationRuleTests.cs
+++ b/PriceChecker.UI.Tests/Validation/ValueCannotBeEmptyValidationRuleTests.cs
@@ -11,7 +11,7 @@ public class ValueCannotBeEmptyValidationRuleTests
         private readonly ValueCannotBeEmptyValidationRule _sut = new();
 
         [Fact]
-        public void Value_is_null__Returns_not_valid()
+        public void Value__Null__Returns_not_valid()
         {
             // Act
             var result = _sut.Validate(null, _fixture.Create<CultureInfo>());
@@ -21,7 +21,7 @@ public void Value_is_null__Returns_not_valid()
         }
 
         [Fact]
-        public void Value_is_not_string__Returns_not_valid()
+        public void Value__Not_string__Returns_not_valid()
         {
             // Act
             var result = _sut.Validate(new object(), _fixture.Create<CultureInfo>());
@@ -31,7 +31,7 @@ public void Value_is_not_string__Returns_not_valid()
         }
 
         [Fact]
-        public void Value_is_null_string__Returns_not_valid()
+        public void Value__Null_string__Returns_not_valid()
         {
             // Arrange
             string value = null;
@@ -44,7 +44,7 @@ public void Value_is_null_string__Returns_not_valid()
         }
 
         [Fact]
-        public void Value_is_empty_string__Returns_not_valid()
+        public void Value__Empty_string__Returns_not_valid()
         {
             // Arrange
             string value = string.Empty;
@@ -57,7 +57,7 @@ public void Value_is_empty_string__Returns_not_valid()
         }
 
         [Fact]
-        public void Value_is_whitespaced_string__Returns_not_valid()
+        public void Value__Whitespaced_string__Returns_not_valid()
         {
             // Arrange
             string value = "   ";
@@ -70,7 +70,7 @@ public void Value_is_whitespaced_string__Returns_not_valid()
         }
 
         [Fact]
-        public void Value_is_string__Returns_valid()
+        public void Value__String__Returns_valid()
         {
             // Arrange
             string value = _fixture.Create<string>();
diff --git a/PriceChecker.UI.Tests/ViewModels/MainViewModelTests.cs b/PriceChecker.UI.Tests/ViewModels/MainViewModelTests.cs
new file mode 100644
index 0000000..a281abf
--- /dev/null
+++ b/PriceChecker.UI.Tests/ViewModels/MainViewModelTests.cs
@@ -0,0 +1,139 @@
+using System.Reactive.Subjects;
+using System.Windows.Shell;
+using AutoFixture;
+using Genius.PriceChecker.UI.Forms;
+using Genius.PriceChecker.UI.Forms.ViewModels;
+using Genius.PriceChecker.UI.Helpers;
+using Genius.PriceChecker.UI.ViewModels;
+using Moq;
+using Xunit;
+
+namespace Genius.PriceChecker.UI.Tests.ViewModels
+{
+    public class MainViewModelTests : TestBase
+    {
+        private readonly TabMock<ITrackerViewModel> _trackerMock = new();
+        private readonly TabMock<IAgentsViewModel> _agentsMock = new();
+        private readonly TabMock<ISettingsViewModel> _settingsMock = new();
+        private readonly TabMock<ILogsViewModel> _logsMock = new();
+        private readonly Mock<ITrackerScanContext> _scanContextMock = new();
+        private readonly Mock<INotifyIconViewModel> _notifyViewModelMock = new();
+
+        private readonly MainViewModel _sut;
+
+        // Session values:
+        private readonly Subject<(TrackerScanStatus Status, double Progress)> _scanProgressSubject = new();
+
+        public MainViewModelTests()
+        {
+            _scanContextMock.SetupGet(x => x.ScanProgress).Returns(_scanProgressSubject);
+
+            _sut = new(_trackerMock.Object, _agentsMock.Object, _settingsMock.Object,
+                _logsMock.Object, _scanContextMock.Object, _notifyViewModelMock.Object);
+        }
+
+        [Fact]
+        public void Constructor__Tabs_are_populated()
+        {
+            // Verify
+            Assert.Equal(4, _sut.Tabs.Count);
+            Assert.Equal(_trackerMock.Object, _sut.Tabs[0]);
+            Assert.Equal(_agentsMock.Object, _sut.Tabs[1]);
+            Assert.Equal(_settingsMock.Object, _sut.Tabs[2]);
+            Assert.Equal(_logsMock.Object, _sut.Tabs[3]);
+        }
+
+        [Fact]
+        public void SelectedTabIndex_changed__Tab_is_Activated_and_old_deactivated()
+        {
+            // Arrange
+            _sut.SelectedTabIndex = 0;
+            _trackerMock.DropHistory();
+            _agentsMock.DropHistory();
+            _settingsMock.DropHistory();
+            _logsMock.DropHistory();
+
+            // Act
+            var settingsTabIndex = 2;
+            _sut.SelectedTabIndex = settingsTabIndex;
+
+            // Verify
+            Assert.True(_trackerMock.OnlyOneDeactivated);
+            Assert.Equal(0, _agentsMock.ActivatedCalls + _agentsMock.DeactivatedCalls);
+            Assert.True(_settingsMock.OnlyOneActivated);
+            Assert.Equal(0, _logsMock.ActivatedCalls + _logsMock.DeactivatedCalls);
+        }
+
+        [Fact]
+        public void ScanProgress_changed__InProgress__Progress_state_highlighted_green()
+        {
+            // Arrange
+            _sut.ProgressState = TaskbarItemProgressState.None;
+            var progress = Fixture.Create<double>();
+
+            // Act
+            _scanProgressSubject.OnNext((TrackerScanStatus.InProgress, progress));
+
+            // Verify
+            Assert.Equal(TaskbarItemProgressState.Normal, _sut.ProgressState);
+            Assert.Equal(progress, _sut.ProgressValue);
+        }
+
+        [Fact]
+        public void ScanProgress_changed__InProgressWithErrors__Progress_state_highlighted_yellow()
+        {
+            // Arrange
+            _sut.ProgressState = TaskbarItemProgressState.None;
+            var progress = Fixture.Create<double>();
+
+            // Act
+            _scanProgressSubject.OnNext((TrackerScanStatus.InProgressWithErrors, progress));
+
+            // Verify
+            Assert.Equal(TaskbarItemProgressState.Paused, _sut.ProgressState);
+            Assert.Equal(progress, _sut.ProgressValue);
+        }
+
+        [Fact]
+        public void ScanProgress_changed__Finished__Progress_state_dropped_and_message_shown()
+        {
+            // Arrange
+            _sut.ProgressState = TaskbarItemProgressState.Normal;
+            _sut.ProgressValue = Fixture.Create<double>();
+
+            // Act
+            _scanProgressSubject.OnNext((TrackerScanStatus.Finished, Fixture.Create<double>()));
+
+            // Verify
+            Assert.Equal(TaskbarItemProgressState.None, _sut.ProgressState);
+            Assert.Equal(0, _sut.ProgressValue);
+        }
+    }
+
+    class TabMock<T> : Mock<T>
+        where T: class, ITabViewModel
+    {
+        public int ActivatedCalls = 0;
+        public int DeactivatedCalls = 0;
+
+        public TabMock()
+        {
+            var activatedCommandMock = new Mock<IActionCommand>();
+            activatedCommandMock.Setup(x => x.Execute(null)).Callback((object _) => ActivatedCalls++);
+            SetupGet(x => x.Activated).Returns(activatedCommandMock.Object);
+
+            var deactivatedCommandMock = new Mock<IActionCommand>();
+            deactivatedCommandMock.Setup(x => x.Execute(null)).Callback((object _) => DeactivatedCalls++);
+            SetupGet(x => x.Deactivated).Returns(deactivatedCommandMock.Object);
+        }
+
+        public void DropHistory()
+        {
+            ActivatedCalls = 0;
+            DeactivatedCalls = 0;
+        }
+
+        public bool OnlyOneActivated => ActivatedCalls == 1 && DeactivatedCalls == 0;
+        public bool OnlyOneDeactivated => ActivatedCalls == 0 && DeactivatedCalls == 1;
+    }
+}
diff --git a/PriceChecker.UI.Tests/ViewModels/TrackerViewModelTests.cs b/PriceChecker.UI.Tests/ViewModels/TrackerViewModelTests.cs
new file mode 100644
index 0000000..7d59db3
--- /dev/null
+++ b/PriceChecker.UI.Tests/ViewModels/TrackerViewModelTests.cs
@@ -0,0 +1,349 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reactive;
+using System.Reactive.Subjects;
+using AutoFixture;
+using Genius.PriceChecker.Core.Messages;
+using Genius.PriceChecker.Core.Models;
+using Genius.PriceChecker.Core.Repositories;
+using Genius.PriceChecker.UI.Forms;
+using Genius.PriceChecker.UI.Helpers;
+using Genius.PriceChecker.UI.ViewModels;
+using Moq;
+using Xunit;
+
+namespace Genius.PriceChecker.UI.Tests.ViewModels
+{
+  public class TrackerViewModelTests : TestBase
+    {
+        private readonly Mock<IProductRepository> _productRepoMock = new();
+        private readonly Mock<IViewModelFactory> _vmFactoryMock = new();
+        private readonly Mock<IUserInteraction> _uiMock = new();
+        private readonly Mock<ITrackerScanContext> _scanContextMock = new();
+
+        // Session values:
+        private readonly Subject<ProductScanStartedEvent> _productScanStartedEventSubject;
+        private readonly Subject<ProductScannedEvent> _productScannedEventSubject;
+        private readonly Subject<ProductScanFailedEvent> _productScanFailedEventSubject;
+
+        public TrackerViewModelTests()
+        {
+            _productScanStartedEventSubject = CreateEventSubject<ProductScanStartedEvent>();
+            _productScannedEventSubject = CreateEventSubject<ProductScannedEvent>();
+            _productScanFailedEventSubject = CreateEventSubject<ProductScanFailedEvent>();
+
+            _vmFactoryMock.Setup(x => x.CreateTrackerProduct(It.IsAny<Product>()))
+                .Returns((Product p) => Mock.Of<ITrackerProductViewModel>(x =>
+                    x.Id == (p == null ? Guid.Empty : p.Id) &&
+                    x.RefreshPriceCommand == Mock.Of<IActionCommand>() &&
+                    x.CommitProductCommand == Mock.Of<IActionCommand>(c => c.Executed == new Subject<Unit>())));
+        }
+
+        [Fact]
+        public void Constructor__RefreshOptions_are_defined_and_list_reloaded()
+        {
+            // Arrange
+            var products = SampleProducts();
+
+            // Act
+            var sut = CreateSystemUnderTest();
+
+            // Verify
+            Assert.NotEmpty(sut.RefreshOptions);
+            Assert.Equal(products.Select(x => x.Id), sut.Products.Select(x => x.Id));
+        }
+
+        [Fact]
+        public void RefreshAllCommand__Enqueues_all_products_for_scan()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.IsAddEditProductVisible = true;
+
+            // Act
+            sut.RefreshAllCommand.Execute(null);
+
+            // Verify
+            Assert.False(sut.IsAddEditProductVisible);
+            _scanContextMock.Verify(x => x.NotifyStarted(products.Count));
+            foreach (var product in sut.Products)
+            {
+                Mock.Get(product.RefreshPriceCommand).Verify(x => x.Execute(null), Times.Once);
+            }
+        }
+
+        [Fact]
+        public void RefreshAllCommand__Enqueues_selected_products_for_scan()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.Products[0].IsSelected = true;
+            sut.Products[2].IsSelected = true;
+
+            // Act
+            sut.RefreshSelectedCommand.Execute(null);
+
+            // Verify
+            _scanContextMock.Verify(x => x.NotifyStarted(2));
+            foreach (var product in sut.Products)
+            {
+                var times = product == sut.Products[0] || product == sut.Products[2] ? Times.Once() : Times.Never();
+                Mock.Get(product.RefreshPriceCommand).Verify(x => x.Execute(null), times);
+            }
+        }
+
+        [Fact]
+        public void OpenAddProductFlyoutCommand__When_flyout_is_closed__Flyout_shows_up()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.IsAddEditProductVisible = false;
+            sut.EditingProduct = null;
+
+            // Act
+            sut.OpenAddProductFlyoutCommand.Execute(null);
+
+            // Verify
+            Assert.True(sut.IsAddEditProductVisible);
+            Assert.NotNull(sut.EditingProduct);
+            Assert.Equal(Guid.Empty, sut.EditingProduct.Id);
+        }
+
+        [Fact]
+        public void OpenAddProductFlyoutCommand__When_flyout_is_opened__Flyout_closed()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.IsAddEditProductVisible = true;
+
+            // Act
+            sut.OpenAddProductFlyoutCommand.Execute(null);
+
+            // Verify
+            Assert.False(sut.IsAddEditProductVisible);
+        }
+
+        [Fact]
+        public void OpenAddProductFlyoutCommand__Product_committed__List_reloaded_and_flyout_closed()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.OpenAddProductFlyoutCommand.Execute(null); // trigger to open flyout
+
+            // Act
+            ((Subject<Unit>)sut.EditingProduct.CommitProductCommand.Executed).OnNext(Unit.Default);
+
+            // Verify
+            Assert.False(sut.IsAddEditProductVisible);
+            _productRepoMock.Verify(x => x.GetAll(), Times.Exactly(2));
+        }
+
+        [Fact]
+        public void OpenEditProductFlyoutCommand__When_flyout_is_closed__Flyout_shows_up()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.IsAddEditProductVisible = false;
+            sut.Products[0].IsSelected = true;
+            sut.EditingProduct = null;
+
+            // Act
+            sut.OpenEditProductFlyoutCommand.Execute(null);
+
+            // Verify
+            Assert.True(sut.IsAddEditProductVisible);
+            Assert.NotNull(sut.EditingProduct);
+            Assert.Equal(products.First().Id, sut.EditingProduct.Id);
+        }
+
+        [Fact]
+        public void OpenEditProductFlyoutCommand__When_flyout_is_opened__Flyout_closed()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.IsAddEditProductVisible = true;
+
+            // Act
+            sut.OpenEditProductFlyoutCommand.Execute(null);
+
+            // Verify
+            Assert.False(sut.IsAddEditProductVisible);
+        }
+
+        [Fact]
+        public void OpenEditProductFlyoutCommand__Product_committed__Flyout_closed()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.Products[0].IsSelected = true;
+            sut.OpenEditProductFlyoutCommand.Execute(null); // trigger to open flyout
+
+            // Act
+            ((Subject<Unit>)sut.EditingProduct.CommitProductCommand.Executed).OnNext(Unit.Default);
+
+            // Verify
+            Assert.False(sut.IsAddEditProductVisible);
+        }
+
+        [Fact]
+        public void DeleteProductCommand__User_confirmed__Flyout_closed_and_product_removed()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.Products[1].IsSelected = true;
+            sut.IsAddEditProductVisible = true;
+            _uiMock.Setup(x => x.AskForConfirmation(It.IsAny<string>(), It.IsAny<string>())).Returns(true);
+
+            // Act
+            sut.DeleteProductCommand.Execute(null);
+
+            // Verify
+            var deletedProductId = products.ElementAt(1).Id;
+            Assert.False(sut.IsAddEditProductVisible);
+            Assert.DoesNotContain(sut.Products, x => x.Id == deletedProductId);
+            Assert.Equal(products.Count - 1, sut.Products.Count);
+            _productRepoMock.Verify(x => x.Delete(deletedProductId));
+        }
+
+        [Fact]
+        public void DeleteProductCommand__User_not_confirmed__Flyout_closed_and_product_remained()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.Products[1].IsSelected = true;
+            sut.IsAddEditProductVisible = true;
+            _uiMock.Setup(x => x.AskForConfirmation(It.IsAny<string>(), It.IsAny<string>())).Returns(false);
+
+            // Act
+            sut.DeleteProductCommand.Execute(null);
+
+            // Verify
+            var deletingProductId = products.ElementAt(1).Id;
+            Assert.False(sut.IsAddEditProductVisible);
+            Assert.Contains(sut.Products, x => x.Id == deletingProductId);
+            Assert.Equal(products.Count, sut.Products.Count);
+            _productRepoMock.Verify(x => x.Delete(deletingProductId), Times.Never);
+        }
+
+        [Fact]
+        public void DeleteProductCommand__No_product_selected__Flyout_closed_and_operation_cancelled()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.IsAddEditProductVisible = true;
+
+            // Act
+            sut.DeleteProductCommand.Execute(null);
+
+            // Verify
+            Assert.False(sut.IsAddEditProductVisible);
+            Assert.Equal(products.Count, sut.Products.Count);
+            _productRepoMock.Verify(x => x.Delete(It.IsAny<Guid>()), Times.Never);
+            _uiMock.Verify(x => x.AskForConfirmation(It.IsAny<string>(), It.IsAny<string>()), Times.Never);
+        }
+
+        [Fact]
+        public void ProductScanStartedEvent_fired__Appropriate_product_changed_status()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            var productScanningIndex = 1;
+
+            // Act
+            _productScanStartedEventSubject.OnNext(new ProductScanStartedEvent(products.ElementAt(productScanningIndex)));
+
+            // Verify
+            Assert.Equal(ProductScanStatus.Scanning, sut.Products[productScanningIndex].Status);
+        }
+
+        [Fact]
+        public void ProductScannedEvent_fired__Appropriate_product_changed_status()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            var lowestUpdated = Fixture.Create<bool>();
+            var productScannedIndex = 1;
+
+            // Act
+            _productScannedEventSubject.OnNext(new ProductScannedEvent(products.ElementAt(productScannedIndex), lowestUpdated));
+
+            // Verify
+            Mock.Get(sut.Products[productScannedIndex]).Verify(x => x.Reconcile(lowestUpdated), Times.Once);
+        }
+
+        [Fact]
+        public void ProductScanFailedEvent_fired__Appropriate_product_set_to_failed()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            var productFailedIndex = 1;
+            var errorMessage = Fixture.Create<string>();
+
+            // Act
+            _productScanFailedEventSubject.OnNext(new ProductScanFailedEvent(products.ElementAt(productFailedIndex), errorMessage));
+
+            // Verify
+            Mock.Get(sut.Products[productFailedIndex]).Verify(x => x.SetFailed(errorMessage), Times.Once);
+        }
+
+        [Fact]
+        public void Deactivated__Flyout_closed()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            sut.IsAddEditProductVisible = true;
+
+            // Act
+            sut.Deactivated.Execute(null);
+
+            // Verify
+            Assert.False(sut.IsAddEditProductVisible);
+        }
+
+        [Fact]
+        public void Product_status_changed__Scan_context_notified()
+        {
+            // Arrange
+            var products = SampleProducts();
+            var sut = CreateSystemUnderTest();
+            var product = sut.Products[1];
+            var status = Fixture.Create<Generator<ProductScanStatus>>()
+                .First(x => x != product.Status);
+
+            // Act
+            RaisePropertyChanged(Mock.Get(product), x => x.Status, status);
+
+            // Verify
+            _scanContextMock.Verify(x => x.NotifyProgressChange(status));
+        }
+
+        private TrackerViewModel CreateSystemUnderTest()
+        {
+            return new TrackerViewModel(EventBusMock.Object, _productRepoMock.Object, _vmFactoryMock.Object,
+                _uiMock.Object, _scanContextMock.Object);
+        }
+
+        private ICollection<Product> SampleProducts()
+        {
+            var products = Fixture.CreateMany<Product>().ToList();
+            _productRepoMock.Setup(x => x.GetAll()).Returns(products);
+            return products;
+        }
+    }
+}
diff --git a/PriceChecker.UI/App.xaml.cs b/PriceChecker.UI/App.xaml.cs
index 0cf5812..4bcec13 100644
--- a/PriceChecker.UI/App.xaml.cs
+++ b/PriceChecker.UI/App.xaml.cs
@@ -62,13 +62,13 @@ private void ConfigureServices(IServiceCollection services)
             // Views, View models, and the View model factory
             services.AddTransient<IViewModelFactory, ViewModelFactory>();
             services.AddTransient<MainWindow>();
-            services.AddTransient<MainViewModel>();
-            services.AddTransient<TrackerViewModel>();
-            services.AddTransient<TrackerProductViewModel>();
-            services.AddTransient<AgentsViewModel>();
-            services.AddTransient<AgentViewModel>();
-            services.AddTransient<SettingsViewModel>();
-            services.AddTransient<LogsViewModel>();
+            services.AddTransient<IMainViewModel, MainViewModel>();
+            services.AddTransient<ITrackerViewModel, TrackerViewModel>();
+            services.AddTransient<ITrackerProductViewModel, TrackerProductViewModel>();
+            services.AddTransient<IAgentsViewModel, AgentsViewModel>();
+            services.AddTransient<IAgentViewModel, AgentViewModel>();
+            services.AddTransient<ISettingsViewModel, SettingsViewModel>();
+            services.AddTransient<ILogsViewModel, LogsViewModel>();
 
             // Services and Helpers:
             services.AddTransient<IUserInteraction, UserInteraction>();
diff --git a/PriceChecker.UI/Helpers/TrackerScanContext.cs b/PriceChecker.UI/Helpers/TrackerScanContext.cs
index 07ef94c..08c5f43 100644
--- a/PriceChecker.UI/Helpers/TrackerScanContext.cs
+++ b/PriceChecker.UI/Helpers/TrackerScanContext.cs
@@ -82,6 +82,8 @@ private double CalculateProgress()
 
         public IObservable<(TrackerScanStatus Status, double Progress)> ScanProgress => _scanProgress;
 
+        public bool IsStarted => _started;
+        public int FinishedJobs => _finished;
         public bool HasErrors { get; private set; }
         public bool HasNewLowestPrice { get; private set; }
     }
diff --git a/PriceChecker.UI/Helpers/UserInteraction.cs b/PriceChecker.UI/Helpers/UserInteraction.cs
index 9aa7353..2a48f05 100644
--- a/PriceChecker.UI/Helpers/UserInteraction.cs
+++ b/PriceChecker.UI/Helpers/UserInteraction.cs
@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Windows;
 using Genius.PriceChecker.Core.Models;
 using Genius.PriceChecker.Core.Repositories;
@@ -30,6 +31,7 @@ public interface IUserInteraction
         void ShowProductInBrowser(ProductSource productSource);
     }
 
+    [ExcludeFromCodeCoverage]
     public class UserInteraction : IUserInteraction
     {
         private readonly IAgentRepository _agentRepo;
diff --git a/PriceChecker.UI/PriceChecker.UI.csproj b/PriceChecker.UI/PriceChecker.UI.csproj
index 06f8e6c..d7a46da 100644
--- a/PriceChecker.UI/PriceChecker.UI.csproj
+++ b/PriceChecker.UI/PriceChecker.UI.csproj
@@ -14,6 +14,11 @@
     <DefineConstants>DEBUG</DefineConstants>
   </PropertyGroup>
 
+  <ItemGroup>
+    <InternalsVisibleTo Include="PriceChecker.UI.Tests" />
+    <InternalsVisibleTo Include="DynamicProxyGenAssembly2" />
+  </ItemGroup>
+
   <ItemGroup>
     <Resource Include="Assets\Logo.ico" />
     <Resource Include="Assets\*.png" />
diff --git a/PriceChecker.UI/ViewModels/AgentViewModel.cs b/PriceChecker.UI/ViewModels/AgentViewModel.cs
index 8c8a193..e2ea5c3 100644
--- a/PriceChecker.UI/ViewModels/AgentViewModel.cs
+++ b/PriceChecker.UI/ViewModels/AgentViewModel.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
@@ -8,19 +9,25 @@
 
 namespace Genius.PriceChecker.UI.ViewModels
 {
-    public class AgentViewModel : ViewModelBase, IHasDirtyFlag, ISelectable
+    public interface IAgentViewModel : IViewModel, IHasDirtyFlag, ISelectable
     {
-        private readonly AgentsViewModel _owner;
+        Agent CreateEntity();
+        void ResetForm();
+
+        string Id { get; }
+    }
+
+    internal sealed class AgentViewModel : ViewModelBase, IAgentViewModel
+    {
+        private readonly IAgentsViewModel _owner;
         private readonly Agent _agent;
 
-        public AgentViewModel(AgentsViewModel owner, Agent agent)
+        public AgentViewModel(IAgentsViewModel owner, Agent agent)
         {
             _owner = owner;
             _agent = agent;
 
             ResetForm(true);
-
-            PropertiesAreInitialized = true;
         }
 
         public Agent CreateEntity()
@@ -33,18 +40,29 @@ public Agent CreateEntity()
             };
         }
 
-        public void ResetForm(bool enforeInitialization = false)
+        public void ResetForm()
         {
-            if (_agent == null && !enforeInitialization)
+            ResetForm(false);
+        }
+
+        private void ResetForm(bool firstTimeInit)
+        {
+            if (_agent == null && !firstTimeInit)
             {
                 return;
             }
-            Id = _agent?.Id;
-            Url = _agent?.Url;
-            PricePattern = _agent?.PricePattern;
-            DecimalDelimiter = _agent?.DecimalDelimiter ?? '.';
 
-            IsDirty = false;
+            Action init = () => {
+                Id = _agent?.Id;
+                Url = _agent?.Url;
+                PricePattern = _agent?.PricePattern;
+                DecimalDelimiter = _agent?.DecimalDelimiter ?? '.';
+            };
+
+            if (firstTimeInit)
+                this.InitializeProperties(init);
+            else
+                init();
         }
 
         [Browsable(false)]
diff --git a/PriceChecker.UI/ViewModels/AgentsViewModel.cs b/PriceChecker.UI/ViewModels/AgentsViewModel.cs
index e11ffe0..34ddc1f 100644
--- a/PriceChecker.UI/ViewModels/AgentsViewModel.cs
+++ b/PriceChecker.UI/ViewModels/AgentsViewModel.cs
@@ -8,7 +8,12 @@
 
 namespace Genius.PriceChecker.UI.ViewModels
 {
-    public class AgentsViewModel : TabViewModelBase, IHasDirtyFlag
+    public interface IAgentsViewModel : ITabViewModel
+    {
+        ObservableCollection<IAgentViewModel> Agents { get; }
+    }
+
+    internal sealed class AgentsViewModel : TabViewModelBase, IAgentsViewModel, IHasDirtyFlag
     {
         private readonly IAgentRepository _agentRepo;
         private readonly IViewModelFactory _vmFactory;
@@ -54,11 +59,9 @@ public AgentsViewModel(IAgentRepository agentRepo, IViewModelFactory vmFactory,
                 }
                 IsDirty = false;
             }, _ => IsDirty);
-
-            PropertiesAreInitialized = true;
         }
 
-        private AgentViewModel CreateAgentViewModel(Agent x)
+        private IAgentViewModel CreateAgentViewModel(Agent x)
         {
             var agentVm = _vmFactory.CreateAgent(this, x);
             agentVm.WhenChanged(x => x.IsDirty, x =>
@@ -81,7 +84,8 @@ private void CommitAgents()
             IsDirty = false;
         }
 
-        public ObservableCollection<AgentViewModel> Agents { get; } = new ObservableCollection<AgentViewModel>();
+        public ObservableCollection<IAgentViewModel> Agents { get; }
+            = new TypedObservableList<IAgentViewModel, AgentViewModel>();
 
         public bool IsAddEditAgentVisible
         {
diff --git a/PriceChecker.UI/ViewModels/LogItemViewModel.cs b/PriceChecker.UI/ViewModels/LogItemViewModel.cs
index bea5948..cbf74ca 100644
--- a/PriceChecker.UI/ViewModels/LogItemViewModel.cs
+++ b/PriceChecker.UI/ViewModels/LogItemViewModel.cs
@@ -8,7 +8,12 @@
 
 namespace Genius.PriceChecker.UI.ViewModels
 {
-    public class LogItemViewModel : ViewModelBase
+    public interface ILogItemViewModel : IViewModel
+    {
+        LogLevel Severity { get; }
+    }
+
+    internal sealed class LogItemViewModel : ViewModelBase, ILogItemViewModel
     {
         public LogItemViewModel()
         {
diff --git a/PriceChecker.UI/ViewModels/LogsViewModel.cs b/PriceChecker.UI/ViewModels/LogsViewModel.cs
index bfd88bc..ffb290f 100644
--- a/PriceChecker.UI/ViewModels/LogsViewModel.cs
+++ b/PriceChecker.UI/ViewModels/LogsViewModel.cs
@@ -10,7 +10,11 @@
 
 namespace Genius.PriceChecker.UI.ViewModels
 {
-  public class LogsViewModel : TabViewModelBase
+    public interface ILogsViewModel : ITabViewModel
+    {
+    }
+
+    internal sealed class LogsViewModel : TabViewModelBase, ILogsViewModel
     {
         public LogsViewModel(IEventBus eventBus)
         {
@@ -28,7 +32,7 @@ public LogsViewModel(IEventBus eventBus)
             LogItems.CollectionChanged += (_, args) => {
                 if (HasNewErrors)
                     return;
-                HasNewErrors = args.NewItems?.Cast<LogItemViewModel>()
+                HasNewErrors = args.NewItems?.Cast<ILogItemViewModel>()
                     .Any(x => x.Severity >= LogLevel.Error) ?? false;
             };
 
@@ -36,7 +40,8 @@ public LogsViewModel(IEventBus eventBus)
             Deactivated.Executed.Subscribe(_ => HasNewErrors = false);
         }
 
-        public ObservableCollection<LogItemViewModel> LogItems { get; } = new ObservableCollection<LogItemViewModel>();
+        public ObservableCollection<ILogItemViewModel> LogItems { get; }
+            = new TypedObservableList<ILogItemViewModel, LogItemViewModel>();
 
         public bool HasNewErrors
         {
diff --git a/PriceChecker.UI/ViewModels/MainViewModel.cs b/PriceChecker.UI/ViewModels/MainViewModel.cs
index 330f7d2..8108459 100644
--- a/PriceChecker.UI/ViewModels/MainViewModel.cs
+++ b/PriceChecker.UI/ViewModels/MainViewModel.cs
@@ -7,16 +7,26 @@
 
 namespace Genius.PriceChecker.UI.ViewModels
 {
-    public class MainViewModel : ViewModelBase
+    public interface IMainViewModel : IViewModel
     {
+    }
+
+    internal sealed class MainViewModel : ViewModelBase, IMainViewModel
+    {
+        private readonly ITrackerScanContext _scanContext;
+        private readonly INotifyIconViewModel _notifyViewModel;
+
         public MainViewModel(
-            TrackerViewModel tracker,
-            AgentsViewModel agents,
-            SettingsViewModel settings,
-            LogsViewModel logs,
+            ITrackerViewModel tracker,
+            IAgentsViewModel agents,
+            ISettingsViewModel settings,
+            ILogsViewModel logs,
             ITrackerScanContext scanContext,
             INotifyIconViewModel notifyViewModel)
         {
+            _scanContext = scanContext;
+            _notifyViewModel = notifyViewModel;
+
             Tabs = new() {
                 tracker,
                 agents,
@@ -24,37 +34,40 @@ public MainViewModel(
                 logs
             };
 
-            scanContext.ScanProgress.Subscribe(args => {
-                if (args.Status == Helpers.TrackerScanStatus.InProgress)
-                {
-                    ProgressState = TaskbarItemProgressState.Normal;
-                    ProgressValue = args.Progress;
-                }
-                else if (args.Status == Helpers.TrackerScanStatus.InProgressWithErrors)
-                {
-                    ProgressState = TaskbarItemProgressState.Paused;
-                    ProgressValue = args.Progress;
-                }
-                else if (args.Status == Helpers.TrackerScanStatus.Finished)
-                {
-                    var message = scanContext.HasNewLowestPrice
-                            ? "Prices for some products have become even lower! Check it out."
-                            : "Nothing interesting has been caught.";
-                    if (scanContext.HasErrors)
-                    {
-                        message += Environment.NewLine + "NOTE: Some products could not finish scanning properly. Check the logs for details.";
-                    }
-                    notifyViewModel.ShowBalloonTip("Scan finished", message,
-                        scanContext.HasErrors ? BalloonIcon.Warning : BalloonIcon.Info);
-                    ProgressState = TaskbarItemProgressState.None;
-                    ProgressValue = 0;
-                }
-                else
+            scanContext.ScanProgress.Subscribe(args => UpdateProgress(args.Status, args.Progress));
+        }
+
+        private void UpdateProgress(TrackerScanStatus status, double progress)
+        {
+            if (status == Helpers.TrackerScanStatus.InProgress)
+            {
+                ProgressState = TaskbarItemProgressState.Normal;
+                ProgressValue = progress;
+            }
+            else if (status == Helpers.TrackerScanStatus.InProgressWithErrors)
+            {
+                ProgressState = TaskbarItemProgressState.Paused;
+                ProgressValue = progress;
+            }
+            else if (status == Helpers.TrackerScanStatus.Finished)
+            {
+                var message = _scanContext.HasNewLowestPrice ?
+                    "Prices for some products have become even lower! Check it out." :
+                    "Nothing interesting has been caught.";
+                if (_scanContext.HasErrors)
                 {
-                    ProgressState = TaskbarItemProgressState.None;
-                    ProgressValue = 0;
+                    message += Environment.NewLine + "NOTE: Some products could not finish scanning properly. Check the logs for details.";
                 }
-            });
+                _notifyViewModel.ShowBalloonTip("Scan finished", message,
+                    _scanContext.HasErrors ? BalloonIcon.Warning : BalloonIcon.Info);
+                ProgressState = TaskbarItemProgressState.None;
+                ProgressValue = 0;
+            }
+            else
+            {
+                ProgressState = TaskbarItemProgressState.None;
+                ProgressValue = 0;
+            }
         }
 
         public List<ITabViewModel> Tabs { get; }
diff --git a/PriceChecker.UI/ViewModels/SettingsViewModel.cs b/PriceChecker.UI/ViewModels/SettingsViewModel.cs
index ee816b2..8bd6a88 100644
--- a/PriceChecker.UI/ViewModels/SettingsViewModel.cs
+++ b/PriceChecker.UI/ViewModels/SettingsViewModel.cs
@@ -4,7 +4,11 @@
 
 namespace Genius.PriceChecker.UI.ViewModels
 {
-    public class SettingsViewModel : TabViewModelBase
+    public interface ISettingsViewModel : ITabViewModel
+    {
+    }
+
+    internal sealed class SettingsViewModel : TabViewModelBase, ISettingsViewModel
     {
         public SettingsViewModel(ISettingsRepository repo)
         {
diff --git a/PriceChecker.UI/ViewModels/TrackerProductSourceViewModel.cs b/PriceChecker.UI/ViewModels/TrackerProductSourceViewModel.cs
index 4619f09..586bea4 100644
--- a/PriceChecker.UI/ViewModels/TrackerProductSourceViewModel.cs
+++ b/PriceChecker.UI/ViewModels/TrackerProductSourceViewModel.cs
@@ -10,16 +10,16 @@
 
 namespace Genius.PriceChecker.UI.ViewModels
 {
-    public class TrackerProductSourceViewModel : ViewModelBase
+    internal sealed class TrackerProductSourceViewModel : ViewModelBase
     {
         public TrackerProductSourceViewModel(IUserInteraction ui, ProductSource productSource, decimal? lastPrice)
         {
-            Id = productSource?.Id ?? Guid.NewGuid();
-            Agent = productSource?.AgentId;
-            Argument = productSource?.AgentArgument;
-            LastPrice = lastPrice;
-
-            PropertiesAreInitialized = true;
+            InitializeProperties(() => {
+                Id = productSource?.Id ?? Guid.NewGuid();
+                Agent = productSource?.AgentId;
+                Argument = productSource?.AgentArgument;
+                LastPrice = lastPrice;
+            });
 
             ShowInBrowserCommand = new ActionCommand(_ => {
                 ui.ShowProductInBrowser(productSource);
diff --git a/PriceChecker.UI/ViewModels/TrackerProductViewModel.cs b/PriceChecker.UI/ViewModels/TrackerProductViewModel.cs
index 50d5b06..bb9323a 100644
--- a/PriceChecker.UI/ViewModels/TrackerProductViewModel.cs
+++ b/PriceChecker.UI/ViewModels/TrackerProductViewModel.cs
@@ -17,11 +17,24 @@
 using Genius.PriceChecker.UI.Forms.ViewModels;
 using Genius.PriceChecker.UI.Helpers;
 using Genius.PriceChecker.UI.ValueConverters;
+using ReactiveUI;
 
 namespace Genius.PriceChecker.UI.ViewModels
 {
+    public interface ITrackerProductViewModel : IViewModel, ISelectable
+    {
+        void Reconcile(bool lowestPriceUpdated);
+        void SetFailed(string errorMessage);
+
+        Guid Id { get; }
+        string Name { get; }
+        ProductScanStatus Status { get; set; }
+        IActionCommand CommitProductCommand { get; }
+        IActionCommand RefreshPriceCommand { get; }
+    }
+
     [ShowOnlyBrowsable(true)]
-    public class TrackerProductViewModel : ViewModelBase, ISelectable
+    internal sealed class TrackerProductViewModel : ViewModelBase, ITrackerProductViewModel
     {
         private readonly IAgentRepository _agentRepo;
         private readonly IProductPriceManager _productMng;
@@ -43,14 +56,16 @@ public TrackerProductViewModel(Product product, IEventBus eventBus,
             _product = product;
             _ui = ui;
 
-            RefreshAgents();
-            RefreshCategories();
+            InitializeProperties(() => {
+                RefreshAgents();
+                RefreshCategories();
 
-            if (_product != null)
-            {
-                ResetForm();
-                Reconcile(false);
-            }
+                if (_product != null)
+                {
+                    ResetForm();
+                    Reconcile(false);
+                }
+            });
 
             CommitProductCommand = new ActionCommand(_ => CommitProduct());
 
@@ -78,17 +93,15 @@ public TrackerProductViewModel(Product product, IEventBus eventBus,
             }, _ => Status != ProductScanStatus.Scanning);
 
             eventBus.WhenFired<AgentsUpdatedEvent, AgentDeletedEvent>()
-                .ObserveOnDispatcher()
+                .ObserveOn(RxApp.MainThreadScheduler)
                 .Subscribe(_ =>
                     RefreshAgents()
                 );
             eventBus.WhenFired<ProductUpdatedEvent, ProductAddedEvent>()
-                .ObserveOnDispatcher()
+                .ObserveOn(RxApp.MainThreadScheduler)
                 .Subscribe(_ =>
                     RefreshCategories()
                 );
-
-            PropertiesAreInitialized = true;
         }
 
         public void Reconcile(bool lowestPriceUpdated)
@@ -272,12 +285,14 @@ public bool IsSelected
         }
 
         public IActionCommand CommitProductCommand { get; }
+
         [Browsable(true)]
         [Icon("Web16")]
         public IActionCommand ShowInBrowserCommand { get; }
         public IActionCommand AddSourceCommand { get; }
         public IActionCommand ResetCommand { get; }
         public IActionCommand DropPricesCommand { get; }
+
         [Browsable(true)]
         [Icon("Refresh16")]
         public IActionCommand RefreshPriceCommand { get; }
diff --git a/PriceChecker.UI/ViewModels/TrackerViewModel.cs b/PriceChecker.UI/ViewModels/TrackerViewModel.cs
index 3cdfbe1..3bd8b9c 100644
--- a/PriceChecker.UI/ViewModels/TrackerViewModel.cs
+++ b/PriceChecker.UI/ViewModels/TrackerViewModel.cs
@@ -11,10 +11,14 @@
 using Genius.PriceChecker.UI.Forms.Attributes;
 using Genius.PriceChecker.UI.Forms.ViewModels;
 using Genius.PriceChecker.UI.Helpers;
+using ReactiveUI;
 
 namespace Genius.PriceChecker.UI.ViewModels
 {
-  public class TrackerViewModel : TabViewModelBase
+    public interface ITrackerViewModel : ITabViewModel
+    { }
+
+    internal sealed class TrackerViewModel : TabViewModelBase, ITrackerViewModel
     {
         private readonly IEventBus _eventBus;
         private readonly IProductRepository _productRepo;
@@ -55,7 +59,7 @@ public TrackerViewModel(IEventBus eventBus,
             });
             OpenEditProductFlyoutCommand = new ActionCommand(o => {
                 EditingProduct = Products.FirstOrDefault(x => x.IsSelected);
-                EditingProduct.CommitProductCommand.Executed
+                EditingProduct?.CommitProductCommand.Executed
                     .Take(1)
                     .Subscribe(_ => {
                         IsAddEditProductVisible = false;
@@ -79,7 +83,7 @@ public TrackerViewModel(IEventBus eventBus,
             });
 
             _eventBus.WhenFired<ProductScanStartedEvent>()
-                .ObserveOnDispatcher()
+                .ObserveOn(RxApp.MainThreadScheduler)
                 .Subscribe(ev =>
                     Products.First(x => x.Id == ev.Product.Id).Status = Core.Models.ProductScanStatus.Scanning
                 );
@@ -101,11 +105,9 @@ public TrackerViewModel(IEventBus eventBus,
             };
 
             ReloadList();
-
-            PropertiesAreInitialized = true;
         }
 
-        private void EnqueueScan(ICollection<TrackerProductViewModel> products)
+        private void EnqueueScan(ICollection<ITrackerProductViewModel> products)
         {
             _scanContext.NotifyStarted(products.Count);
             foreach (var product in products)
@@ -129,9 +131,10 @@ private void ReloadList()
             Products.ReplaceItems(productVms);
         }
 
-        public static List<DropDownMenuItem> RefreshOptions { get; private set; }
+        public List<DropDownMenuItem> RefreshOptions { get; private set; }
 
-        public ObservableCollection<TrackerProductViewModel> Products { get; } = new ObservableCollection<TrackerProductViewModel>();
+        public ObservableCollection<ITrackerProductViewModel> Products { get; }
+            = new TypedObservableList<ITrackerProductViewModel, TrackerProductViewModel>();
 
         [FilterContext]
         public string Filter
@@ -146,9 +149,9 @@ public bool IsAddEditProductVisible
             set => RaiseAndSetIfChanged(value);
         }
 
-        public TrackerProductViewModel EditingProduct
+        public ITrackerProductViewModel EditingProduct
         {
-            get => GetOrDefault<TrackerProductViewModel>();
+            get => GetOrDefault<ITrackerProductViewModel>();
             set => RaiseAndSetIfChanged(value);
         }
 
diff --git a/PriceChecker.UI/ViewModels/ViewModelFactory.cs b/PriceChecker.UI/ViewModels/ViewModelFactory.cs
index 23266b8..86611f0 100644
--- a/PriceChecker.UI/ViewModels/ViewModelFactory.cs
+++ b/PriceChecker.UI/ViewModels/ViewModelFactory.cs
@@ -1,3 +1,4 @@
+using System.Diagnostics.CodeAnalysis;
 using Genius.PriceChecker.Core.Models;
 using Genius.PriceChecker.Core.Repositories;
 using Genius.PriceChecker.Core.Services;
@@ -8,11 +9,12 @@ namespace Genius.PriceChecker.UI.ViewModels
 {
     public interface IViewModelFactory
     {
-        AgentViewModel CreateAgent(AgentsViewModel owner, Agent agent);
-        TrackerProductViewModel CreateTrackerProduct(Product product);
+        IAgentViewModel CreateAgent(IAgentsViewModel owner, Agent agent);
+        ITrackerProductViewModel CreateTrackerProduct(Product product);
     }
 
-    public class ViewModelFactory : IViewModelFactory
+    [ExcludeFromCodeCoverage]
+    internal sealed class ViewModelFactory : IViewModelFactory
     {
         private readonly IAgentRepository _agentRepo;
         private readonly IProductRepository _productRepo;
@@ -35,12 +37,12 @@ public ViewModelFactory(IEventBus eventBus,
             _ui = ui;
         }
 
-        public AgentViewModel CreateAgent(AgentsViewModel owner, Agent agent)
+        public IAgentViewModel CreateAgent(IAgentsViewModel owner, Agent agent)
         {
             return new AgentViewModel(owner, agent);
         }
 
-        public TrackerProductViewModel CreateTrackerProduct(Product product)
+        public ITrackerProductViewModel CreateTrackerProduct(Product product)
         {
             return new TrackerProductViewModel(product, _eventBus, _agentRepo,
                 _productPriceMng, _productRepo, _statusProvider, _ui);
diff --git a/PriceChecker.UI/Views/MainWindow.xaml.cs b/PriceChecker.UI/Views/MainWindow.xaml.cs
index 588ed74..d3ea768 100644
--- a/PriceChecker.UI/Views/MainWindow.xaml.cs
+++ b/PriceChecker.UI/Views/MainWindow.xaml.cs
@@ -7,7 +7,7 @@ namespace Genius.PriceChecker.UI.Views
     [ExcludeFromCodeCoverage]
     public partial class MainWindow : MetroWindow
     {
-        public MainWindow(MainViewModel mainVm)
+        public MainWindow(IMainViewModel mainVm)
         {
             InitializeComponent();
 
diff --git a/PriceChecker.UI/Views/Tracker.xaml b/PriceChecker.UI/Views/Tracker.xaml
index 3934352..8b477a1 100644
--- a/PriceChecker.UI/Views/Tracker.xaml
+++ b/PriceChecker.UI/Views/Tracker.xaml
@@ -23,7 +23,7 @@
                     Command="{Binding OpenEditProductFlyoutCommand}" />
             <mah:DropDownButton Content="Refresh" Width="Auto"
                     Padding="5,2" Margin="10,0,0,0"
-                    ItemsSource="{Binding Source={x:Static vm:TrackerViewModel.RefreshOptions}}">
+                    ItemsSource="{Binding RefreshOptions}">
                 <mah:DropDownButton.Icon>
                     <Image Source="{StaticResource Refresh16}" />
                 </mah:DropDownButton.Icon>