Hi, Laurence!
When I group some rows and hide 'em, cell comments change their height. Some comments collapse to zero-height. Code sample to reproduce:
// create comment
int commentIndex = excel.Worksheets[0].Comments.Add(11, 0);
Comment comment = excel.Worksheets[0].Comments[commentIndex];
comment.Note = "Hello!";
// group some rows
excel.Worksheets[0].Outline.SummaryRowBelow = true;
excel.Worksheets[0].Cells.GroupRows(11, 12, true);
excel.Worksheets[0].Cells.GroupRows(14, 17, true);
excel.Worksheets[0].Cells.GroupRows(10, 18, true);
Is there any workaround? Or maybe this bug is easy to fix?