diff --git a/UI/Controls/MultiValueAutoCompleteBox.axaml b/UI/Controls/MultiValueAutoCompleteBox.axaml
new file mode 100644
index 0000000..6616642
--- /dev/null
+++ b/UI/Controls/MultiValueAutoCompleteBox.axaml
@@ -0,0 +1,39 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
+             x:Class="TagHierarchyManager.UI.Controls.MultiValueAutoCompleteBox"
+             xmlns:controls="clr-namespace:TagHierarchyManager.UI.Controls"
+             xmlns:vm="clr-namespace:TagHierarchyManager.UI.ViewModels">
+    <Grid>
+        <TextBox Name="MultiValueAutoCompleteBoxTextBox"
+                 Text="{Binding Text,
+                 RelativeSource={RelativeSource AncestorType=controls:MultiValueAutoCompleteBox}}"
+                 Watermark="{Binding Watermark,
+                 RelativeSource={RelativeSource AncestorType=controls:MultiValueAutoCompleteBox}}"
+                 TextChanged="TextBox_OnTextChanged"
+                 GotFocus="TextBox_OnGotFocus" LostFocus="TextBox_OnLostFocus"/>
+        
+        <Popup Name="MultiValueAutoCompletePopup"
+               Placement="Bottom"
+               IsLightDismissEnabled="False"
+               IsOpen="False">
+            <Border CornerRadius="10" Background="#555555">
+                <ListBox Name="MultiValueAutoCompleteListBox"
+                         SelectionMode="Single"
+                         MaxHeight="500"
+                         SelectionChanged="ListBox_OnSelectionChanged">
+                    <ListBox.ItemTemplate>
+                        <DataTemplate x:DataType="vm:TagItemViewModel">
+                            <TextBlock Text="{Binding CurrentName}"/>
+                        </DataTemplate>
+                    </ListBox.ItemTemplate>
+                </ListBox>
+            </Border>
+            
+                  
+              
+        </Popup>
+    </Grid>
+</UserControl>
diff --git a/UI/Controls/MultiValueAutoCompleteBox.axaml.cs b/UI/Controls/MultiValueAutoCompleteBox.axaml.cs
new file mode 100644
index 0000000..33f2e31
--- /dev/null
+++ b/UI/Controls/MultiValueAutoCompleteBox.axaml.cs
@@ -0,0 +1,139 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Data;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.Reactive;
+using TagHierarchyManager.UI.ViewModels;
+
+namespace TagHierarchyManager.UI.Controls;
+
+public partial class MultiValueAutoCompleteBox : UserControl
+{
+    public MultiValueAutoCompleteBox()
+    {
+        InitializeComponent();
+        this.MultiValueAutoCompletePopup.PlacementTarget = this.MultiValueAutoCompleteBoxTextBox;
+        this.MultiValueAutoCompleteListBox.ItemsSource = this.FilteredItems;
+        this.MultiValueAutoCompleteBoxTextBox
+            .GetPropertyChangedObservable(BoundsProperty)
+            .Subscribe(new AnonymousObserver<AvaloniaPropertyChangedEventArgs>(
+                e => this.MultiValueAutoCompleteListBox.Width = ((Rect)e.NewValue!).Width));
+    }
+    
+    public static readonly StyledProperty<string> TextProperty =
+        AvaloniaProperty.Register<MultiValueAutoCompleteBox, string>(
+            nameof(Text), defaultValue: string.Empty, defaultBindingMode: BindingMode.TwoWay);
+    
+    public static readonly StyledProperty<string> WatermarkProperty =
+        AvaloniaProperty.Register<MultiValueAutoCompleteBox, string>(
+            nameof(Watermark), defaultValue: string.Empty);
+    
+    public static readonly StyledProperty<IEnumerable<TagItemViewModel>?> ItemsSourceProperty =
+        AvaloniaProperty.Register<MultiValueAutoCompleteBox, IEnumerable<TagItemViewModel>?>(
+            nameof(ItemsSource), defaultValue: []);
+
+    private bool _isTextBoxFocused;
+    
+    private bool CanShowPopup => this._isTextBoxFocused && this.FilteredItems.Any();
+    
+    public string Text
+    {
+        get => GetValue(TextProperty);
+        set => SetValue(TextProperty, value);
+    }
+    
+    public string Watermark
+    {
+        get => GetValue(WatermarkProperty);
+        set => SetValue(WatermarkProperty, value);
+    }
+    
+    public IEnumerable<TagItemViewModel>? ItemsSource
+    {
+        get => GetValue(ItemsSourceProperty);
+        set => SetValue(ItemsSourceProperty, value);
+    }
+    
+    public ObservableCollection<TagItemViewModel> FilteredItems { get; set; } = [];
+
+    private string _lastTypedRawText = string.Empty;
+    
+    public void TextBox_OnTextChanged(object? sender, TextChangedEventArgs e)
+    {
+        if (sender is not TextBox box) return;
+        var rawText = box.Text ?? string.Empty;
+        if (box.Text == this._lastTypedRawText) return;
+        this._lastTypedRawText = rawText;
+        this.Text = rawText;
+    }
+    
+    private void TextBox_OnGotFocus(object? sender, GotFocusEventArgs e)
+    {
+        this._isTextBoxFocused = true;
+    }
+    
+    private void TextBox_OnLostFocus(object? sender, RoutedEventArgs e)
+    {
+        this._isTextBoxFocused = false;
+        this.UpdatePopupIsVisible();
+    }
+    
+    protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+    {
+        base.OnPropertyChanged(change);
+        System.Diagnostics.Debug.WriteLine($"CanShowPopup: {this.CanShowPopup}, focused: {this._isTextBoxFocused}, items: {this.FilteredItems.Count}");
+        if (change.Property == TextProperty)
+        {
+            var last = this.Text.Split(';').Last();
+            last = last.Trim();
+            this.RepopulateFilteredItems(last);
+        }
+    }
+    
+    private void RepopulateFilteredItems(string itemName)
+    {
+        this.FilteredItems.Clear();
+
+        if (!string.IsNullOrWhiteSpace(itemName) && this.ItemsSource is not null)
+        {
+            var filtered = this.ItemsSource
+                .Where(t => t.CurrentName.Contains(itemName, StringComparison.OrdinalIgnoreCase))
+                .ToList();
+            foreach (var item in filtered)
+                this.FilteredItems.Add(item);
+            
+        }
+        
+        this.UpdatePopupIsVisible();
+    }
+
+    private bool _isApplyingSelection;
+    private void UpdatePopupIsVisible()
+    {
+        if (this._isApplyingSelection) return;
+        this.MultiValueAutoCompletePopup.IsOpen = this.CanShowPopup;
+    }
+    
+    private void ListBox_OnSelectionChanged(object? sender, SelectionChangedEventArgs e)
+    {
+        if (sender is not ListBox listBox || listBox.SelectedItem is not TagItemViewModel tag) return;
+        this._isApplyingSelection = true;
+        listBox.SelectedItem = null;
+        
+        var lastSemicolon = this._lastTypedRawText.LastIndexOf(';');
+        var prefix = lastSemicolon >= 0 ? this._lastTypedRawText[..(lastSemicolon)].TrimEnd() + "; " : string.Empty;
+        var result = $"{prefix}{tag.CurrentName}";
+        this.Text = result;
+        this.MultiValueAutoCompletePopup.IsOpen = false;
+        this.MultiValueAutoCompleteBoxTextBox.Text = result;
+        this.MultiValueAutoCompleteBoxTextBox.CaretIndex = result.Length;
+        this.MultiValueAutoCompleteBoxTextBox.Focus();
+        this._lastTypedRawText = result;
+        this._isApplyingSelection = false;
+    }
+}
\ No newline at end of file