Disable auto-fill

[E Rosenberg]

Dear list -

Pardon me for resending this.

This is not a random question.  My wife's and my economic stability depend
on the answer.

Is there a mechanism to disable auto-fill?  When I attempt to add a
transaction to the checkbook, it deletes half of the previous transaction:
ie, credit/debit transaction, it will delete either the credit or debit
side, I think the last transaction entered.

TIA

Ethan Rosenberg