When a column is collapsed (e.g., to save space), and later expanded again, the column header should return with its original rowspan configuration instead of resetting to default per-row header cells.
Current Behavior:
Upon collapsing and then expanding a column, the header text (e.g., "Trip") does not retain its previous formatting.
It appears with the header repeated for each row, or misaligned vertically. Expected Behavior:
On expand, the header should restore a single cell spanning all rows (i.e., rowspan=N) with vertical text formatting like: