Hello, Ken,      

Note that the CellFormatting/ViewCellFormatting events are purposed to style the cells that are displayed in the grid. Due to the UI virtualization in RadGridView, cell elements are created only for currently visible cells and are being reused during operations like scrolling, filtering, grouping and so on. Hence, the CellFormatting/ViewCellFormatting events are fired only for the visible cells.

I can suggest you to expand the desired rows after you populate the grid with data. Then, you can iterate the RadGridView.Rows collection which stores the data rows and set the IsExpanded property to the desired value.

However, if you are still experiencing any further difficulties, it would be greatly appreciated if you can give us some more details about the exact scenario that you have and the specific requirement that you are trying to accomplish. Thus, we would get better understanding of the precise case and think about a suitable solution.

I hope this information helps. If you need any further assistance please don't hesitate to contact me. 

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik