diff --git a/samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml b/samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml
index f90a0c4658..a49616e543 100644
--- a/samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml
+++ b/samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml
@@ -51,6 +51,11 @@
                          Width="200"
                          Margin="0,0,0,8"
                          FilterMode="None"/>
+        <TextBlock Text="Custom Autocomplete"/>
+        <AutoCompleteBox Name="CustomAutocompleteBox"
+                         Width="200"
+                         Margin="0,0,0,8"
+                         FilterMode="None"/>
       </StackPanel>
     </StackPanel>
   </StackPanel>
diff --git a/samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml.cs b/samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml.cs
index f9d6a72a3a..574cc79a7d 100644
--- a/samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml.cs
+++ b/samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml.cs
@@ -92,13 +92,28 @@ namespace ControlCatalog.Pages
         }
         public StateData[] States { get; private set; }
         
+        private LinkedList<string>[] BuildAllSentences()
+        {
+            return new string[]
+            {
+                "Hello world",
+                "No this is Patrick",
+                "Never gonna give you up",
+                "How does one patch KDE2 under FreeBSD"
+            }
+            .Select(x => new LinkedList<string>(x.Split(' ')))
+            .ToArray();
+        }
+        public LinkedList<string>[] Sentences { get; private set; }
+
         public AutoCompleteBoxPage()
         {
             this.InitializeComponent();
 
             States = BuildAllStates();
+            Sentences = BuildAllSentences();
 
-            foreach (AutoCompleteBox box in GetAllAutoCompleteBox())
+            foreach (AutoCompleteBox box in GetAllAutoCompleteBox().Where(x => x.Name != "CustomAutocompleteBox"))
             {
                 box.Items = States;
             }
@@ -116,6 +131,11 @@ namespace ControlCatalog.Pages
 
             var asyncBox = this.FindControl<AutoCompleteBox>("AsyncBox");
             asyncBox.AsyncPopulator = PopulateAsync;
+
+            var customAutocompleteBox = this.FindControl<AutoCompleteBox>("CustomAutocompleteBox");
+            customAutocompleteBox.Items = Sentences.SelectMany(x => x);
+            customAutocompleteBox.TextFilter = LastWordContains;
+            customAutocompleteBox.TextSelector = AppendWord;
         }
         private IEnumerable<AutoCompleteBox> GetAllAutoCompleteBox()
         {
@@ -137,6 +157,42 @@ namespace ControlCatalog.Pages
                       .ToList();
         }
 
+        private bool LastWordContains(string searchText, string item)
+        {
+            var words = searchText.Split(' ');
+            var options = Sentences.Select(x => x.First).ToArray();
+            for (var i = 0; i < words.Length; ++i)
+            {
+                var word = words[i];
+                for (var j = 0; j < options.Length; ++j)
+                {
+                    var option = options[j];
+                    if (option == null)
+                        continue;
+
+                    if (i == words.Length - 1)
+                    {
+                        options[j] = option.Value.ToLower().Contains(word.ToLower()) ? option : null;
+                    }
+                    else
+                    {
+                        options[j] = option.Value.Equals(word, StringComparison.InvariantCultureIgnoreCase) ? option.Next : null;
+                    }
+                }
+            }
+
+            return options.Any(x => x != null && x.Value == item);
+        }
+        private string AppendWord(string text, string item)
+        {
+            string[] parts = text.Split(' ');
+            if (parts.Length == 0)
+                return item;
+
+            parts[parts.Length - 1] = item;
+            return string.Join(" ", parts);
+        }
+
         private void InitializeComponent()
         {
             AvaloniaXamlLoader.Load(this);
diff --git a/samples/RenderDemo/MainWindow.xaml b/samples/RenderDemo/MainWindow.xaml
index 770960d7c4..93fbe5e412 100644
--- a/samples/RenderDemo/MainWindow.xaml
+++ b/samples/RenderDemo/MainWindow.xaml
@@ -3,8 +3,8 @@
         x:Class="RenderDemo.MainWindow"
         Title="AvaloniaUI Rendering Test"
         xmlns:pages="clr-namespace:RenderDemo.Pages"
-        Width="800"
-        Height="600">
+        Width="{Binding Width, Mode=TwoWay}"
+        Height="{Binding Height, Mode=TwoWay}">
   <DockPanel>
     <Menu DockPanel.Dock="Top">
       <MenuItem Header="Rendering">
@@ -24,6 +24,10 @@
           </MenuItem.Icon>
         </MenuItem>
       </MenuItem>
+      <MenuItem Header="Tests">
+        <MenuItem Header="Resize window"
+                  Command="{Binding ResizeWindow}"/>
+      </MenuItem>
     </Menu>
     <TabControl Classes="sidebar">
       <TabItem Header="Animations">
diff --git a/samples/RenderDemo/ViewModels/MainWindowViewModel.cs b/samples/RenderDemo/ViewModels/MainWindowViewModel.cs
index d2d789a687..eda5e80530 100644
--- a/samples/RenderDemo/ViewModels/MainWindowViewModel.cs
+++ b/samples/RenderDemo/ViewModels/MainWindowViewModel.cs
@@ -1,5 +1,6 @@
-using System;
-using System.Reactive;
+using System.Reactive;
+using System.Threading.Tasks;
+
 using ReactiveUI;
 
 namespace RenderDemo.ViewModels
@@ -8,26 +9,61 @@ namespace RenderDemo.ViewModels
     {
         private bool drawDirtyRects = false;
         private bool drawFps = true;
+        private double width = 800;
+        private double height = 600;
 
         public MainWindowViewModel()
         {
             ToggleDrawDirtyRects = ReactiveCommand.Create(() => DrawDirtyRects = !DrawDirtyRects);
             ToggleDrawFps = ReactiveCommand.Create(() => DrawFps = !DrawFps);
+            ResizeWindow = ReactiveCommand.CreateFromTask(ResizeWindowAsync);
         }
 
         public bool DrawDirtyRects
         {
-            get { return drawDirtyRects; }
-            set { this.RaiseAndSetIfChanged(ref drawDirtyRects, value); }
+            get => drawDirtyRects;
+            set => this.RaiseAndSetIfChanged(ref drawDirtyRects, value);
         }
 
         public bool DrawFps
         {
-            get { return drawFps; }
-            set { this.RaiseAndSetIfChanged(ref drawFps, value); }
+            get => drawFps;
+            set => this.RaiseAndSetIfChanged(ref drawFps, value);
+        }
+
+        public double Width
+        {
+            get => width;
+            set => this.RaiseAndSetIfChanged(ref width, value);
+        }
+
+        public double Height
+        {
+            get => height;
+            set => this.RaiseAndSetIfChanged(ref height, value);
         }
 
         public ReactiveCommand<Unit, bool> ToggleDrawDirtyRects { get; }
         public ReactiveCommand<Unit, bool> ToggleDrawFps { get; }
+        public ReactiveCommand<Unit, Unit> ResizeWindow { get; }
+
+        private async Task ResizeWindowAsync()
+        {
+            for (int i = 0; i < 30; i++)
+            {
+                Width += 10;
+                Height += 5;
+                await Task.Delay(10);
+            }
+
+            await Task.Delay(10);
+
+            for (int i = 0; i < 30; i++)
+            {
+                Width -= 10;
+                Height -= 5;
+                await Task.Delay(10);
+            }
+        }
     }
 }
diff --git a/src/Avalonia.Controls/AutoCompleteBox.cs b/src/Avalonia.Controls/AutoCompleteBox.cs
index 6bbb4f0b75..bfd633c947 100644
--- a/src/Avalonia.Controls/AutoCompleteBox.cs
+++ b/src/Avalonia.Controls/AutoCompleteBox.cs
@@ -227,6 +227,27 @@ namespace Avalonia.Controls
         Custom = 13,
     }
 
+    /// <summary>
+    /// Represents the selector used by the
+    /// <see cref="T:Avalonia.Controls.AutoCompleteBox" /> control to
+    /// determine how the specified text should be modified with an item.
+    /// </summary>
+    /// <returns>
+    /// Modified text that will be used by the
+    /// <see cref="T:Avalonia.Controls.AutoCompleteBox" />.
+    /// </returns>
+    /// <param name="search">The string used as the basis for filtering.</param>
+    /// <param name="item">
+    /// The selected item that should be combined with the
+    /// <paramref name="search" /> parameter.
+    /// </param>
+    /// <typeparam name="T">
+    /// The type used for filtering the
+    /// <see cref="T:Avalonia.Controls.AutoCompleteBox" />.
+    /// This type can be either a string or an object.
+    /// </typeparam>
+    public delegate string AutoCompleteSelector<T>(string search, T item);
+
     /// <summary>
     /// Represents a control that provides a text box for user input and a
     /// drop-down that contains possible matches based on the input in the text
@@ -364,6 +385,9 @@ namespace Avalonia.Controls
         private AutoCompleteFilterPredicate<object> _itemFilter;
         private AutoCompleteFilterPredicate<string> _textFilter = AutoCompleteSearch.GetFilter(AutoCompleteFilterMode.StartsWith);
 
+        private AutoCompleteSelector<object> _itemSelector;
+        private AutoCompleteSelector<string> _textSelector;
+
         public static readonly RoutedEvent<SelectionChangedEventArgs> SelectionChangedEvent =
             RoutedEvent.Register<SelectionChangedEventArgs>(nameof(SelectionChanged), RoutingStrategies.Bubble, typeof(AutoCompleteBox));
 
@@ -530,6 +554,34 @@ namespace Avalonia.Controls
                 (o, v) => o.TextFilter = v,
                 unsetValue: AutoCompleteSearch.GetFilter(AutoCompleteFilterMode.StartsWith));
 
+        /// <summary>
+        /// Identifies the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemSelector" />
+        /// dependency property.
+        /// </summary>
+        /// <value>The identifier for the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemSelector" />
+        /// dependency property.</value>
+        public static readonly DirectProperty<AutoCompleteBox, AutoCompleteSelector<object>> ItemSelectorProperty =
+            AvaloniaProperty.RegisterDirect<AutoCompleteBox, AutoCompleteSelector<object>>(
+                nameof(ItemSelector),
+                o => o.ItemSelector,
+                (o, v) => o.ItemSelector = v);
+
+        /// <summary>
+        /// Identifies the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.TextSelector" />
+        /// dependency property.
+        /// </summary>
+        /// <value>The identifier for the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.TextSelector" />
+        /// dependency property.</value>
+        public static readonly DirectProperty<AutoCompleteBox, AutoCompleteSelector<string>> TextSelectorProperty =
+            AvaloniaProperty.RegisterDirect<AutoCompleteBox, AutoCompleteSelector<string>>(
+                nameof(TextSelector),
+                o => o.TextSelector,
+                (o, v) => o.TextSelector = v);
+
         /// <summary>
         /// Identifies the
         /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />
@@ -1063,6 +1115,40 @@ namespace Avalonia.Controls
             set { SetAndRaise(TextFilterProperty, ref _textFilter, value); }
         }
 
+        /// <summary>
+        /// Gets or sets the custom method that combines the user-entered
+        /// text and one of the items specified by the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />.
+        /// </summary>
+        /// <value>
+        /// The custom method that combines the user-entered
+        /// text and one of the items specified by the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />.
+        /// </value>
+        public AutoCompleteSelector<object> ItemSelector
+        {
+            get { return _itemSelector; }
+            set { SetAndRaise(ItemSelectorProperty, ref _itemSelector, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the custom method that combines the user-entered
+        /// text and one of the items specified by the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />
+        /// in a text-based way.
+        /// </summary>
+        /// <value>
+        /// The custom method that combines the user-entered
+        /// text and one of the items specified by the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />
+        /// in a text-based way.
+        /// </value>
+        public AutoCompleteSelector<string> TextSelector
+        {
+            get { return _textSelector; }
+            set { SetAndRaise(TextSelectorProperty, ref _textSelector, value); }
+        }
+
         public Func<string, CancellationToken, Task<IEnumerable<object>>> AsyncPopulator
         {
             get { return _asyncPopulator; }
@@ -2331,6 +2417,14 @@ namespace Avalonia.Controls
             {
                 text = SearchText;
             }
+            else if (TextSelector != null)
+            {
+                text = TextSelector(SearchText, FormatValue(newItem, true));
+            }
+            else if (ItemSelector != null)
+            {
+                text = ItemSelector(SearchText, newItem);
+            }
             else
             {
                 text = FormatValue(newItem, true);
diff --git a/src/Avalonia.Themes.Fluent/Button.xaml b/src/Avalonia.Themes.Fluent/Button.xaml
index e58e8758d2..021c6eae1d 100644
--- a/src/Avalonia.Themes.Fluent/Button.xaml
+++ b/src/Avalonia.Themes.Fluent/Button.xaml
@@ -77,7 +77,7 @@
     <Setter Property="TextBlock.Foreground" Value="{DynamicResource AccentButtonForegroundPressed}" />
   </Style>
 
-  <Style Selector="Button">
+  <Style Selector=":is(Button)">
     <Setter Property="RenderTransform" Value="none" />
     <Setter Property="Transitions">
       <Transitions>
@@ -86,7 +86,7 @@
     </Setter>
   </Style>
 
-  <Style Selector="Button:pressed">
+  <Style Selector=":is(Button):pressed">
     <Setter Property="RenderTransform" Value="scale(0.98)" />    
   </Style>
 
diff --git a/tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs b/tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs
index 57cea91834..3e78e951e2 100644
--- a/tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs
@@ -363,6 +363,40 @@ namespace Avalonia.Controls.UnitTests
             });
         }
         
+        [Fact]
+        public void Custom_TextSelector()
+        {
+            RunTest((control, textbox) =>
+            {
+                object selectedItem = control.Items.Cast<object>().First();
+                string input = "42";
+
+                control.TextSelector = (text, item) => text + item;
+                Assert.Equal(control.TextSelector("4", "2"), "42");
+
+                control.Text = input;
+                control.SelectedItem = selectedItem;
+                Assert.Equal(control.Text, control.TextSelector(input, selectedItem.ToString()));
+            });
+        }
+        
+        [Fact]
+        public void Custom_ItemSelector()
+        {
+            RunTest((control, textbox) =>
+            {
+                object selectedItem = control.Items.Cast<object>().First();
+                string input = "42";
+
+                control.ItemSelector = (text, item) => text + item;
+                Assert.Equal(control.ItemSelector("4", 2), "42");
+
+                control.Text = input;
+                control.SelectedItem = selectedItem;
+                Assert.Equal(control.Text, control.ItemSelector(input, selectedItem));
+            });
+        }
+
         /// <summary>
         /// Retrieves a defined predicate filter through a new AutoCompleteBox 
         /// control instance.