To delete a transaction, first select the transaction you wish to delete. Then click the Delete Payment or Delete Bill button.
A message will appear asking you to confirm the delete action. After choosing Yes, the payment/bill will no longer appear in the transaction list.
If the transaction you choose to delete has more than one split a message will appear asking you if you want to delete the entire transaction with all its splits.
To delete an individual split, you need to edit the transaction and use the Delete button in the Payment or Bills screen to delete that individual split.