Hello Charles, 

Thank you for following up. I've reproduced and isolated the behavior with SeriesMouseLeftButtonUp. I've logged a development issue (# 260269) with our developers to investigate this further and opened a private case ( CAS-199686-C3N9S2 ) to provide you with further updates regarding our investigation. You may visit the case from the support activities section > In development tab from your account. 

As a workaround you may use SeriesMouseLeftButtonDown. Also I didn't see any issues with the enter/leave series events. They don't seem to exhibit any problems with our samples. I will update you within the case to investigate this further. 

If you have any additional questions please use the case as well. Thanks. 

private void ultraGeographicMap1_SeriesMouseEnter(object sender, Infragistics.Win.DataVisualization.ChartMouseEventArgs e)
{
    ultraGeographicMap1.Cursor = System.Windows.Forms.Cursors.Hand;

    MapSymbol symbol = e?.Item as MapSymbol;
    if (symbol != null)
    {
        //*Process symbol*
    }
}

private void ultraGeographicMap1_SeriesMouseLeave(object sender, Infragistics.Win.DataVisualization.ChartMouseEventArgs e)
{
    ultraGeographicMap1.Cursor = System.Windows.Forms.Cursors.Default;

    if (ultraPopupControlContainer1.IsDisplayed)
    {
        ultraPopupControlContainer1.Close();

        if (ultraPopupControlContainer1.PopupControl != null)
        {
            ultraPopupControlContainer1.PopupControl.Dispose();
        }
    }
}

private void ultraGeographicMap1_SeriesMouseLeftButtonUp(object sender, Infragistics.Win.DataVisualization.ChartMouseButtonEventArgs e)
{
    MapSymbol symbol = e?.Item as MapSymbol;
    
    //*Process symbol*
}

Here are the events we are using. Basically, we are trying to pull an item we attached to the map data and present it in a popup. This works find for point data and mostly fine for polyline data, but the events do not fire for polygon data.

I tried different settings for ContentHitTestMode on the UltraGeographicMap control, but none seemed to work for polygon data. I did notice that if that property is set to Computational, then polyline data stopped working.

Thanks for your help.