At first, I couldn't always reproduce this, as it happens only when a new fee account is added to a new transaction.
In a new Dividend transaction, if an interest account is added and then a fee account, when the fee wizard is closed, the interest account name has been deleted.

Reproducible: Always

Steps to Reproduce:
1. Create a new Dividend transaction.
2. Enter a new interest account and value.
3. Enter a new fee account name and complete the wizard.
4. When the wizard is closed, the interest name field has been cleared.

Actual Results:  
As in 4. above.

Expected Results:  
The interest account name should not be cleared, as happens if an existing transaction is edited instead of a new one being created.

InvestTransactionEditor::slotReloadEditWidgets() gets called and because splits.count() is zero, 
case 0: in the switch instruction is entered, where category->clearEditText() clears the interest account name.
I'm unclear why that instruction is there and removing it resolves the problem, and so far I see no ill effects.
Can anyone see why it might need to be there, please?