Opera mail - additional email addresses
I have several contacts that use more than one email address
In order to group them under one contact name I used the additional email address available in properties
The emails then appear under one contact but in the inbox they are showing an additional label of the additional email. When I check the labels there is no entry for me to uncheck!
It's a bug with multiple email addresses in a contact. Unfortunately, Opera Mail is no longer being developed, so it will never be fixed.
You'll have to use separate contacts with one address each and unique display names (so you can tell the difference) where you then group them in a contact folder.
Or, if it's not for composing and just sorting messages, you can create a label under the "Labels" access point for each contact where you add a rule to match that email address. The first label would have rules for all the addresses for a contact. Then, there'd be a separate label (with a single rule) for each email address. Then, you can drag those labels into the first to nest them.
You can also click an email address in the header bar of a message and choose follow contact. You'll then get a followed contacts access point in the mail panel and an entry in the contacts panel.