Thank you so much.
But in your project, you use C1.Win.C1FlexGrid.2, which version of C1 do you use?
In my project, I use C1.Win.C1FlexGrid.C1FlexGrid
When I set the fixed row =4
and I have a "for..." loop to set my merged row, I have a result like picture below:

How can you tell me why?
I send my project in the link: http://www.yousendit.com/transfer.php?action=batch_download&batch_id=UXlqK0drdGpubHpIRGc9PQ
Thank you again!!
Overview my code:
fg.Rows.Count = 10;
fg.Cols.Count = 100;
fg.Rows.Fixed = 4;
fg.Cols.Fixed = 0;
int iCell = 4;
CellRange rng = new CellRange();
rng = fg.GetCellRange(0, 0, 2, 3);
rng.Data = "Title Here";
string[] str = new string[10];
for (int i = 0; i < 10; i++)
{
str[i] = "Cell range " + i.ToString();
}
for (int i = 0; i < 10; i++)
{
rng = fg.GetCellRange(0, iCell, 0, iCell + 2);
rng.Data = str[i];
iCell = iCell + 2;
}
fg.AllowMerging = AllowMergingEnum.Free;
for (int i = 0; i <= fg.Cols.Count - 1; i++)
{
fg.Cols[i].AllowMerging = true;
}