When validation is active in radgrid cell, cannot lost focus from cell.

[kity]

When validation is active in radgrid cell, cannot lost focus from cell.
Standart red border in cell apear from IDataErrorInfo when triger validation according inner business logic.
But why cannot change cursor from current edit cell with error? Cannot change cursor focus to other cell.

Why?

<telerik:RadGridView x:Name="NASA_PriorityShips" ItemsSource="{Binding ShipCollections, Mode=TwoWay}"
                      SelectionMode="Single" SelectedItem="{Binding Path=SelectedShip, Mode=TwoWay}"
                      AutoGenerateColumns="False" ShowGroupPanel="False" RowIndicatorVisibility="Collapsed"
                      ColumnWidth="*" CanUserFreezeColumns="False">

                     
workaround: Must press key "Esc" to undo changes in cell, validation will be set to none active.

I set ActionOnLostFocus="None" but the same as first one.

<telerik:RadGridView x:Name="NASA_PriorityShips" ActionOnLostFocus="None" ItemsSource="{Binding ShipCollections, Mode=TwoWay}"
                      SelectionMode="Single" SelectedItem="{Binding Path=SelectedShip, Mode=TwoWay}" 
                      AutoGenerateColumns="False" ShowGroupPanel="False" RowIndicatorVisibility="Collapsed"
                      ColumnWidth="*" CanUserFreezeColumns="False">
                     
                     
ActionOnLostFocus="None" in RadGridView not work at all.