I've been given the task to migrate a 3.5 WPF app with WPFToolkit Datagrid to WPF 4.0 with built in datagrid.
The style for type DataGridColumnHeader is no longer applied?
<Style x:Key="ColumnHeaderStyle" TargetType="{x:Type DataGridColumnHeader}">
<!-- Setters goes here -->
</Style>
edit: Problem was that in 4.0 you cant have a key name for default styles for a specific type, but in 3.5 you could. Solved it like this
<Style TargetType="{x:Type DataGridColumnHeader}">
<!-- Setters goes here -->
</Style>
<Style x:Key="ColumnHeaderStyle" TargetType="{x:Type DataGridColumnHeader}" BasedOn="{StaticResource {x:Type DataGridColumnHeader}}">
</Style>