issue with wpf datagrid cell style when scrolling

Question

I created a new DataGridCell style for my wpf datagrid (Red Border brush). When I scroll down vertically the selected cells disappear which is ok. When I scroll up I see the

Answer 1

Without any more details I can only guess that artifacts you're experiencing are a result of reusing of virtualized cells. You can test this by disabling column and row virtualization:

<DataGrid EnableRowVirtualization="False" EnableColumnVirtualization="False" ...

Also, if this doesn't help did you by any chance override the Equals method of your data items? ItemsControls occasionally glitch when they display several equal items.