In ‘General ledger’ - ‘Reports’ - ‘Balance list with group total accounts’
Opening form, clicking ‘From’ in ‘Ledger account’. Pressing Ctrl+G -as it shown in screenshot ‘Account name’ field is inactive. But in field ‘Main account’ I can search by typing.
You want see the lookup in the personalization of the source form. These are two separate forms and the lookup is likely generated at runtime.
I don’t currently have access to AX, nevertheless I agree it’s a display method and you can’t filter by methods. You will have to implement a new lookup, if the requirement is important enough.