Repro case for https://github.com/AvaloniaUI/Avalonia/issues/10598

MainWindow.axaml.cs

using System;
using System.Collections.Generic;
using System.Linq;

using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.Templates;
using Avalonia.Markup.Xaml;
using Avalonia.Media;
using Avalonia.Media.TextFormatting;

namespace ReproCase
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            this.AttachDevTools();

            AvaloniaXamlLoader.Load(this);

            ListBox listBox = new ListBox();

            listBox.DataTemplates.Add(new FuncDataTemplate<string>((_, _) =>
                new TextBlockAutoTooltip()
                {
                    TextTrimming = TextTrimming.CharacterEllipsis
                }, true));

            List<string> items = new List<string>();
            for (int i = 0; i < 10000; i++)
            {
                if (i % 2 == 0)
                {
                    items.Add(string.Format("Item number {0} which needs a tooltip because it's long text", i));
                }
                {
                    items.Add("Short Item");
                }
            }

            listBox.Items = items;

            this.Content = listBox;
        }

        public class TextBlockAutoTooltip : TextBlock
        {
            protected override void OnDataContextChanged(EventArgs e)
            {
                base.OnDataContextChanged(e);

                if (DataContext == null)
                    return;

                Text = DataContext.ToString();
            }

            protected override TextLayout CreateTextLayout(string text)
            {
                TextLayout result = base.CreateTextLayout(text);
                SetupTooltipVisibility(result);
                return result;
            }

            void SetupTooltipVisibility(TextLayout layout)
            {
                if (TextTrimming == TextTrimming.None)
                    return;

                bool showTooltip = !string.IsNullOrEmpty(Text) &&
                    layout.TextLines.Any(line => line.HasCollapsed);

                if (showTooltip)
                    ToolTip.SetTip(this, Text);
                else
                    ToolTip.SetTip(this, null);
            }
        }
    }
}