Please provide the Full Data Grid Column Header Control Template for customization.  The DataGrid Column Header content template is useful but we would like full control of the Column Header Control Template.

Add the ability to specify a template when the ItemsSource is null or collection is empty.

As a solution until this feature is implemented:

Hide the DataGrid and show any content over it in the case its ItemsSource is empty.

Provide support for nested properties with null values. 

Currently when using the following scenario: null ref exception is throw, when manager is null:

private Person _manager;
public Person Manager
{
    get { return _manager; }
    set { UpdateValue(ref _manager, value); }
}

<telerik:DataGridTextColumn PropertyName="Manager.Name" 
                            HeaderText="Manager"/>

Provide support for null values when nested properties are used in datagrid columns.