Created attachment 370279 [details]
Stack trace of crash

When entering a split transaction where one of the outputs is to a commodity account, GnuCash crashes on exiting the "Transfer Funds" dialog.

Steps to Reproduce:

0. You'll need three accounts for the reproduction: a Checking account, an Investment account (I've been using a Mutual Fund account), and an income account.

1. Open the transaction ledger for the Checking account and start entering a new split transaction (made up numbers):

Deposit to checking: 1000
Withdraw from income: 1500
Deposit to investment: 500

When you hit "Enter" (or "Tab") to move off of the last line, the Transfer Funds dialog opens automatically.

2. Enter some amount in the "Exchange Rate" (or "To Amount") field and hit "Enter" to close the dialog.

Actual Results:

Crash and dump core.

Expected Results:

The transaction is recorded.

Environment:

Arch Linux
Occurs on 2.7.8-6-g82f31a5e4+ but not 2.7.6.