public class AutoCompleteBox : XamComboEditor
    {
        public int MruListMax
        {
            get { return (int)GetValue(MruListMaxProperty); }
            set { SetValue(MruListMaxProperty, value); }
        }

        // Using a DependencyProperty as the backing store for MruListMax.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MruListMaxProperty =
            DependencyProperty.Register("MruListMax", typeof(int), typeof(AutoCompleteBox), new PropertyMetadata(50));

        public AutoCompleteBox()
        {
            this.CustomValueEnteredAction = CustomValueEnteredActions.Add;
            DropDownButtonDisplayMode = DropDownButtonDisplayMode.Never;
        }
        protected override void OnItemAdded(ComboEditorItem item)
        {
            base.OnItemAdded(item);
           
            ObservableCollection<string> itemSourceLIst = this.ItemsSource as ObservableCollection<string>;
            if (itemSourceLIst.Count > MruListMax)
            {
                itemSourceLIst.RemoveAt(0);
            }
        }

    }

And the AutocompleteBox has been added to the view as shown here:

    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        <Controls:AutoCompleteBox ItemsSource="{Binding MruList}" VerticalAlignment="Top" />
        <ListBox ItemsSource="{Binding MruList}"
                 Grid.Column="1" />
     
    </Grid>

My problem is that i do not add the correct new item. If my MruList contains the following : Dennis, Denny, and I enter "Denni" in the comboBoxEditor, the when I click Enter or uses Tab, it do not add "Denni" to the MruList, instead it chooses "Dennis" which are already in the list?

How can I prevent it from suggesting "Dennis", when i only type in "Denni"?

Best Regards!

Dennis

Using 15.1