I'm having a similar issue, but it only seems to happen when I have a ListBox bound to to a collection of ObservableCollection<string>, and I add strings with identical content.

[tracydemery36]

I'm having a similar issue, but it only seems to happen when I have a ListBox bound to to a collection of ObservableCollection<string>, and I add strings with identical content.

            <ListBox AutoScrollToSelectedItem="True"
                   Grid.Row="1"
                   ScrollViewer.HorizontalScrollBarVisibility="Disabled"
                   SelectedIndex="{Binding SIndex}"
                   Items="{Binding LogItems}">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding .}" TextWrapping="Wrap" />
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>

        private ObservableCollection<string> LogItems { get; } = new ObservableCollection<string>();

        private int _sIndex;
        public int SIndex {
            get { return _sIndex; }
            set { this.RaiseAndSetIfChanged(ref _sIndex, value); }
        }

        public void Log(string s) {
            var lines = s.Split('\n');
            foreach (var line in lines) {
                if (!string.IsNullOrWhiteSpace(line)) {
                    LogItems.Add($"{DateTime.Now.ToString("HH:mm tt")}: {line}");
                    SIndex = LogItems.Count - 1;
                }
            }
        }

Originally posted by @lenonk in #2569 (comment)

[FoggyFinder]

This was fixed. Otherwise, can you provide MCVE?

[grokys]

Closing as should be fixed, and no MVCE from reporter.