Stack trace:

Type: KeyNotFoundException

Message: Arg_KeyNotFound
   at Telerik.Data.Core.Layouts.StaggeredRenderInfo.PhysicalOffsetFromSlot(Int32 slot)
   at Telerik.Data.Core.Layouts.StaggeredLayout.PhysicalOffsetFromSlot(Int32 slot)
   at Telerik.UI.Xaml.Controls.Data.ListViewModel.ScrollIndexIntoView(UI.Xaml.Controls.Primitives.ScrollIntoViewOperation<System.Nullable<Telerik.Data.Core.Layouts.ItemInfo>> operation)
   at Telerik.UI.Xaml.Controls.Data.ListViewModel.<>c__DisplayClass55_0.<ScrollIndexIntoViewCore>b__0()
   at System.Action.Invoke()
   at Telerik.UI.Xaml.Controls.Primitives.DelegateUpdate<Telerik.UI.Xaml.Controls.Grid.UpdateFlags>.Process()
   at Telerik.UI.Xaml.Controls.Primitives.UpdateServiceBase<Telerik.UI.Xaml.Controls.Data.ListView.UpdateFlags>.ProcessUpdatesQueue()
   at Telerik.UI.Xaml.Controls.Primitives.UpdateServiceBase<Telerik.UI.Xaml.Controls.Data.ListView.UpdateFlags>.DispatchUpdates()
   at Telerik.UI.Xaml.Controls.Primitives.UpdateServiceBase<Telerik.UI.Xaml.Controls.Data.ListView.UpdateFlags>.OnUpdateCallback()

Version of Telerik.UI.for.UniversalWindowsPlatform 1.0.0.3

In some specific scenarios, scrolling the RadDataGrid results in IndexOutOfRangeException

Exception = {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 startInde...

In a scenario where you have lots of columns so that a horizontal scrollbar is present and you try to resize columns which are not visible at the beginning(need to scroll to view them) ->  the resizing is not working as expected and the view is jumping. 

See this Screencast for a short video of the issue at runtime: https://www.screencast.com/t/YXm6xOtO 

Here's the code to reproduce: 

<grid:RadDataGrid ItemsSource="{x:Bind ViewModel.DataItems, Mode=OneWay}"
                  UserGroupMode="Disabled"
                  UserFilterMode="Disabled"
                  UserColumnReorderMode="None"
                  UserSortMode="None"
                  AutoGenerateColumns="False"
                  GridLinesVisibility="Horizontal">
    <grid:RadDataGrid.Columns>
        <grid:DataGridNumericalColumn Header="1"
                                      PropertyName="Key"
                                      SizeMode="Auto" />
        <grid:DataGridTextColumn Header="2"
                                 PropertyName="First"
                                 SizeMode="Auto" />
        <grid:DataGridTextColumn Header="3"
                                 PropertyName="Second"
                                 SizeMode="Auto" />
        <grid:DataGridTextColumn Header="Stretchy"
                                 PropertyName="Stretch"
                                 SizeMode="Auto" />
        <grid:DataGridTextColumn Header="5"
                                 PropertyName="SecondLast"
                                 SizeMode="Auto" />
        <grid:DataGridTextColumn Header="6"
                                 PropertyName="Last"
                                 SizeMode="Auto" />
        <grid:DataGridNumericalColumn Header="7"
                                      PropertyName="Count"
                                      SizeMode="Auto" />
    </grid:RadDataGrid.Columns>
</grid:RadDataGrid>

TelerikChartAxisBorderBrush is not applied when setting in Dark Light ThemeResources from the Telerik Theme Resources https://docs.telerik.com/devtools/universal-windows-platform/common/teleriknamedbrushes 

Range is rendered incorrectly when using negative range values.

System.Runtime.InteropServices.COMException is thrown when navigating through the child items of the RadialMenuItem. It is easily reproducible when clicking fast to go to the most inner child items of a RadialMenuItem.

When you set the Required attribute on a property of an object that is used for the DataForm, it is not respected by the control.