The controls for which Cash Manager Account is targeted by transactions is based on the transaction type setting in the following location:
From the Toolbar select System Admin, Setup.
Scroll to and select Transaction Types.
Select the Transaction Type which you wish to target a certain Cash Manager Account
Select the Interface tab and check the Updates Bank Account option is set to Yes. This will be defaulted to Yes for Purchase transaction types but Sales transaction types this is an editable option.
In the Always Updates Account field, either:
Enter the Cash Manager Account
Leave the field empty. This will then target the default Cash Manager Account.
Set the field to ? to cause a prompt to appear asking which Cash Manager Account to target.