Hello Wu,

I'm closing the case for now, but If you have any other queries, don't hesitate to contact us again.

Regards,
Dimitar Dinev
Progress Telerik

Hi Wu,

Thank you for the screenshot.

The behavior you observe is expected. The reason for this is the ScrollViewer inside of the ComboBox ControlTemplate. Its CanContentScroll property is set to True by default, which makes the scrolling item by item and because of this there is some space left after the last item.

In order to remove that space you can set the CanContentScroll attached property of the ScrollViewer to False.

Another approach would be to set the Grid in the DataTemplate to a fixed height and set the ComboBox's MaxDropDownHeight property to a number multiple of the Grid's height.

Attached, you can find a sample project demonstrating these approaches. Please, review it and let me know if that answers your query.

Regards,
Dimitar Dinev
Progress Telerik