When the DataGrid is grouped, show the column headers in the group header and allow for aggregates like Sum

I have a radgrid and when I scroll down it throws this error, but I'm not sure where the error is coming from or how I can help resolve it.

This is a UWP app and I'm debugging in VS 2017 15.3 on windows 10 creators edition.

System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at Telerik.UI.Xaml.Controls.Grid.IndexStorage.ValueForIndex(Int32 index, Boolean approximate)
   at Telerik.Data.Core.Layouts.CompactLayout.UpdateAverageLength(Int32 startIndex, Int32 endIndex)
   at Telerik.UI.Xaml.Controls.Grid.NodePool`2.MeasureVertically(RadSize availableSize, Double offset, Double bufferScale)
   at Telerik.UI.Xaml.Controls.Grid.NodePool`2.OnMeasure(RadSize availableSize, Double offset, Int32 frozenEleme

It should be similar like the RealizedItemsVerticalBufferScale, but to work for the horizontal part of the ViewPort.

When you have several series(ScatterLineSeries reported but it happens with others as well) in the RadCartesianChart and you clear the Items of one of them by calling the Clear() method - the line is not redrawn and it shows the old data. 

When using shp and dbf files with ~130MB size, it takes minutes to load the map

The uwp radlistview vertical scrollbar disappears when focus is lost -
I think I need something like 
https://www.telerik.com/forums/listview-width-with-or-without-vertical-scrollbar
 <telerik:RadListView.Commands. ListElement.Scroller.Scrollbar.FillElement.Visibility

But I may be missing something?

A docking control similar to what is available in UI for Silverlight.

This would let us create LOB applications consistent with the Look & Feel of Office 2016 Universal apps.

ListView: Expose setter for SelectedItem property and implement it, so that setting this property applies the corresponding style to the selected item.

Declined: The SelectedItem property has public setter. Setting it makes the style be applied as expected on the item.

Implement a feature which will allow users to change the trigger which updates the source in Editing Mode

Testing the Telerik RadialMenu control in the UWP app ,  when you click on the radialmenu the control flickers for the mouseclick event on desktop.  plse consider changing the "flicker" to something more like a keypress , a image blur or something else. Or slow down the flicker considerable , your effect looks more like a defect of image rendering at the moment. 

Allow the user to define axis ticks origin value. E.g. with Min=-10, Max=100, MajorStep=25, the user should be able to define that the axis will have ticks and labels at 0, 25, 50, 75 and 100 while keeping the minimum value of -10 in range.