I am evaluating Pivot table and need to nest column groups within group in the header. There's no direct way in Pivot as in Datatable so I tried customizing using "onBeforeRender" as suggested by you. One level of grouping works fine but the open/close gets messed if you added second grouping/level. Similar behavior can be seen in Datatable in below snippet ...
If I open "Feb" and try to close "2008" it doesnt close properly.
Further more in using Pivot, and after configuring the structure, the column grouping state (i.e open/close, colspan etc) is all lost.
Pls let me know if this can be fixed or if there is any way around.