Hello James,

You can create multi row header in IGridHeader. Note, that by design the header consists of a single row. Also the header has as many cells as the number of the columns in the grid are. To create a multi row header you can first create the necessary top level cell in your header. Then add a grid in any header cell where you need multi row header. Then add however rows and columns you need and set the cells spans as you need them. Attached is a small sample showing how you can achieve this.

Please, check my sample and let me know if this is what you are looking for or if I am missing something.