`LineSeries` tooltip not visible when using `DateTimePoint`

Describe the bug Tool tip displays as expected for LineSeries<float> but not when you use the exact same code for LineSeries<DateTimePoint>. Any guidance you can provide would be appreciated.

To Reproduce

Steps to reproduce the behavior:

1. Display a simple line series.
2. Mouse over a data point.

In XAML:

        <lvc:CartesianChart x:Name="CartesianChart" Grid.Row="0" Grid.Column="0"
            XAxes="{Binding XAxes}"
            YAxes="{Binding YAxes}"
            Series="{Binding Series}"
            TooltipPosition="Top"/>

In the constructor:

LiveCharts.Configure(
settings => settings
	.AddDefaultMappers()
	.AddSkiaSharp()
	.AddDarkTheme());

When the Series property is called, the following is returned:

private ISeries[] GetSeries(ImmutableArray<IRecord> records)
{
	var values = new ObservableCollection<float>();
               
         // Does not work
	// var values = new ObservableCollection<DateTimePoint>();

	foreach (var record in records)
	{
		values.Add(record.value);

                              // Does not work
		// values.Add(new DateTimePoint(record.CreatedAt, record.value));
	}

	return new ISeries[]
	{
		// Does not work
		// new LineSeries<DateTimePoint>

		// works
		new LineSeries<float>
		{
			Name = "SeriesName",
			Values = values,
			TooltipLabelFormatter = (chartPoint) => $"TOOLTIP: {chartPoint.Context.Series.Name}: {chartPoint.PrimaryValue}",
		}
	};

Expected behavior

• LineSeries<float> displays the tooltip as expected when you mouse over a data point.

Actual Behavior

• Using LineSeries<DateTimePoint> and the exact same code… a tooltip is not displayed.

Screenshots

• OS: Windows 10 Pro, 64 bit, Version 21H1, Build 19043.1526
• .NET Framework: 4.8
• NuGet package: 2.0.0-beta.90

Additional context

• None at this time.

[Pressacco]

Thank you for the response @beto-rodriguez.

BTW - cool library 👍

[beto-rodriguez]

Thanks for the issue and the feedback.

Yes you are right @Pressacco The UnitWidth is necessary in this case, it fixes your issue. I am thinking in a way to simplify this but I think that it will be enough if we explain better in the docs how to handle DateTime plots, I extended the docs in the referenced commits, and changed the DateTime/TimeSpan samples to explain that this step is required.

About your second query about the repeated point in the tooltip, I also agree, we normally only want to see the closest point to the pointer, so that is how the library will behave by default in the next release, but we could also configure the chart to behave as it does now.

I will close this for now since you found a solution for your issue, your second issue will be gone when you update to the next release of the library.