Hello,
An interesting feature would be to be able to define “recognized” domains (for example those of the company for a pro account) for which email addresses would be displayed normally when writing a message (a:, cc: … fields). The other addresses would then be displayed differently (for example in red).
We find this on some mail clients such as Mail on macOS for example. It’s very useful to make sure we don’t unintentionally send an email to the outside from a work account.