private void IssuesList_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e) { if (e.Button == MouseButtons.Right && !IssuesList.Rows[e.RowIndex].Selected) { while (IssuesList.SelectedRows.Count > 0) IssuesList.SelectedRows[0].Selected = false; IssuesList.Rows[e.RowIndex].Selected = true; } }