Sort by any column visible in the register - including reconciliation status
Like QuickBooks, it is often of use to view the register sorted by reconciliation status so that if checks have been written yet not yet cashed, I can get a one-to-one comparison (including running totals) with what the bank has. That way, all the still outstanding transactions yet to post at the bank (including very old ones that may need to be voided) show up at the bottom of the register, and the last reconciled transaction above it shows the correct current balance in the account.
Because there are only 3 different states sorting makes not much sense. You should use View→Filter by→Status tab instead.