RadGridView has a specific style for the cells belonging to pinned columns coming from the theme. In order to customize the cells, it is appropriate to use the CellFormatting events:
I hope this information helps. Should you have further questions I would be glad to help.
Regards,
Dess
Telerik
Check out the Windows Forms project converter, which aids the conversion process from standard Windows Forms applications written in C# or VB to Telerik UI for WinForms.For more information check out this blog post and share your thoughts.