RadGridView.ValidationType property will be available with R2 2016. 

The functionality is documented at http://docs.telerik.com/devtools/wpf/controls/radgridview/filtering/icolumn-filter-descriptors and for the time being the functionality can be achieved by implementing an attached behavior. 

Scrolling performance is degraded when RowStyle/RowStyleSelector that sets Template property is explicitly applied

Empty cells appear when the RadGridView contains many cells in the viewport and the view gets resized.

To work this around you can extract and modify the ControlTemplate of GridViewCell, in order to set the MinHeight property of the "PART_ContentPresenter" element to a number close to the RowHeight of the RadGridView control.

Column groups may disappear when the RadGridView control is hosted in a TabItem of TabControl. These column groups can disappear when new GridViewColumnGroup instances are created.

Furthermore, resizing a column of RadGridView will result in a NullReferenceException.

To work this around, set the EnableColumnGroupsVirtualization property of RadGridView to False.

ClipboardCopyMode enumeration will expose a new property - SkipNullOrEmptyValue - setting whether null/empty value will be copied or not. Thus if copying cells from a column with multiple empty values, will not have a result in the pasted text, but rather be skipped.

The vertical scrolling seems to become very slow and even unresponsive, when the following conditions are met:

• left and right frozen columns count is 0
• the summary width of all columns is smaller than the width of the RadGridView element

To minimize the issue, you can set the GroupRenderMode property of RadGridView to Nested.

To work around the issue, set the EnableColumnGroupsVirtualization property of RadGridView to True.

The problem should be resolved with Q1 2016.