Default bank account should be selectable

Its annoying that I have to select the Bank Account to use every single transaction, it should be possible to select a default account to use and only change it when necessary. eg I have just the main business account and a petty cash account, 99% of the time I have to select the main account because the field is empty by default. If it were possible to set the default to my main account then I would only need to select the rare times i use petty cash.