RadGrid GridDateTimeColumnEditor is unable to process data of type TimeSpan if PickerType is set to TimePicker.

As a workaround, a GridTemplateColumn can be used with a TimePicker inside EditTemplate

<telerik:GridTemplateColumn>
	<ItemTemplate>
		<%# Eval("Field") %>
	</ItemTemplate>
	<EditItemTemplate>
		<telerik:RadTimePicker ID="RadTimePicker1" runat="server" SelectedTime='<%# Bind("Field") %>'></telerik:RadTimePicker>
	</EditItemTemplate>
</telerik:GridTemplateColumn>