Tom Profile > Settings. There's a toggle. But as long as you're still in a Euro-country, this toggle doesn't change anything anyway because the feature is only activated in non-Euro countries.
If you're asking about payments that you made from your Euro-denominated sub-account in another currency, these were always just displayed in Euro. This feature hasn't changed anything about that. The original amount can always be found in the payment description, though.
I think it would be a nice new idea to also be able to choose to see the local currency that payments originated in, even if the sub-account is denominated in another currency. But that's unrelated to this feature.