A white zoom arrow () indicates that you can display more detailed information about a transaction and make changes to or delete the transaction.
A grey zoom arrow () allows you to display more detailed information about a transaction, but the information is read-only (that is, it cannot be changed). If you want to change the information, you can reverse the transaction and re-enter it (see Reversing a transaction). Alternatively, you can change your security preference selection to make all transactions changeable (see Set up preferences).