How to format Group header

[Gen]

Hello,

I have a gridView with some custom columns: | Name | Department | hours_week1 | hours_week2 | hours_week3 | hours_week4 | ...
Columns hours_week have an aggregate function as follow:

sumFunction = new SumFunction();
sumFunction.SourceField = radTimeLineGridView.Columns[i].UniqueName;
sumFunction.ResultFormatString = "{0:f2}";
radTimeLineGridView.Columns[i].AggregateFunctions.Add(sumFunction);

 When I group by the Department column, the sum of each column is shown in the group header, but it's not following the columns layout. Please see attached image.
How can I force the header to be formatted as the columns?

Also, I want to hide/show some columns. How can I make sure the group headers hide/show the same values? Right now, they show everything, even if some columns are hidden.

Thanks,
Gen

[Janick Ross]

See this post for solution.