Short version: Sparrow won't delete those tabs one at a time. In the source (AppController.java) the right-click "Delete Account" item is only added when the account is not the master wallet and not a Whirlpool child, so Deposit, Premix, Postmix and Bad Bank never get it. Whirlpool itself was removed back in 1.9.0. What does work: 1. Open Premix, Postmix and Bad Bank and check they're empty. If not, send those coins to Deposit first. 2. If you care about labels: File > Export Wallet > Labels (BIP329), then import them into the new wallet later. 3. File > New Wallet, import the same seed (same passphrase and script type) and just don't use Add Account > Whirlpool. That wallet has only the one account. 4. Once the balance matches, close the old one and use File > Delete Wallet... That deletes the old wallet file and its backups, not your coins. Keep your seed backup.

GitHub

sparrow/src/main/java/com/sparrowwallet/sparrow/AppController.java at master · sparrowwallet/sparrow

Desktop Bitcoin Wallet focused on security and privacy. Free and open source. - sparrowwallet/sparrow