The class Telerik.Windows.Data.QueryableExtensions has a static dictionary "providerIsEntityFrameworkCore"

That dictionary will hold a reference (forever) to a collection that is set as Source for the GridView.

Reason is that non IQueryable-types will be wrapped in a EnumerableQuery<T> that will return itself as the provider (https://referencesource.microsoft.com/#System.Core/System/Linq/SequenceQuery.cs,44), encapsulating the reference.

This must be something introduced recently.

You are able to resize columns using the columns gripper. The corresponding group will be automatically resized. We can provide a way to resize the column groups. The columns inside the group will be automatically resized with the group.

At the moment the GridViewNewRow can be placed at the top or at the bottom. Placing it between the rows will require new virtualization mechanism. 

This behavior is reproducible when the HorizontalAligment property of the control or its parent element is set to Left.

Changing the TextAlignment property of the GridViewExpressionColumn doesn't refresh the cells, thus the change is not visible in the UI.

To work this around, remove and add again the corresponding column in the Columns collection of RadGridView. Or define a CellTemplate and use a TextBlock control with its TextAlignment bound to the column's property.

<telerik:GridViewExpressionColumn.CellTemplate>
	<DataTemplate>
		<TextBlock Text="{Binding}" 
				   TextAlignment="{Binding RelativeSource={RelativeSource AncestorType=telerik:GridViewCell}, Path=Column.TextAlignment}"  />
	</DataTemplate>
</telerik:GridViewExpressionColumn.CellTemplate>

In this particular case, the DisplayIndex properties of the parent and child grid are bound to property from our ViewModel. When the parent grid columns are reordered runtime, the columns of the child grid are also reordered. But when sorting is performed by clicking on a column header, an exception is thrown.

Memory leak appears when exporting to Xlsx and Pdf formats.

To work this around, you can call one of the export methods GridViewDataControlExportExtensions with empty arguments.

Workbook workbook = this.gridView.ExportToWorkbook();
try
{
	GridViewDataControlExportExtensions.ExportToWorkbook(new RadGridView(), new GridViewDocumentExportOptions());
	GridViewDataControlExportExtensions.ExportToWorkbook(null);
}
catch (ArgumentException)
{
}        

If the DisplayIndex of the columns is set when they are initialized, ColumnGroups are not displayed.

As a workaround, you can set the DisplayIndex after the columns are initialized.