Hello Brad,
Finally, I manage to reproduce the problem.
The reason I couldn't was that my NDataGridView control was hosted in Form instead of NForm.
When you apply a Longhorn palette to the NUIManager, NForm.ForeColor takes its value from it. For Longhorn palette this color is white.
On the other hand the controls hosted in Form or NForm (NForm subclass Form) inherits this property and NDataGridView.DefaultCellStyle.ForeColor takes its value from the form that resides. Therefore NDataGridView.DefaultCellStyle.ForeColor becomes white.
NDataGridView inherits DataGridView and this "feature" comes from base DataGridView control.
As a solution, I can suggest explicitly to set NDataGridView.DefaultCellStyle.ForeColor to Black or other suitable color.
Best Regards,
Nevron Support Team