Another standard feature that Opera's built-in mail client is missing is support for server-side searching via the IMAP search command.
. select Inbox
. search text zipzambam
. search subject zipzambam
. search body zipzambam
. search from email@example.com
The search command returns a list of IDs of messages that match.
Using the server to search is great when you don't have the bodies for all your messages cached locally, as it allows you to search the bodies without downloading them.
Thunderbird, Mulberry and SquirrelMail have a search UI for this. Sylpheed doesn't though, but when using ctrl + shift + f, it will *automatically* (which has pros and cons) fetch bodies for messages in the view you're searching so that the search can work fully.
Opera doesn't support this at all and searching in bodies only works for messages that have their bodies already downloaded. By default, Opera only fetches the body of a message when you open it. This means that searching is rather crippled by default. You can set "make all messages available offline", which will solve this problem. But, in some cases, it's just not desirable to have the mail folder take up that much space, especially by default.
Even if Opera fetched all bodies by default, server-side searching would still be useful when you want to search only a certain part of a message. Currently, Opera's search field searches the entire message and if you want to search only a specific part, you have to use a label and a rule.
It would be cool if Opera had a "Search messages' UI where you could choose to search on the server and pick what IMAP folder to search in and what part of the message to search in (by choosing one of the search keys supported by the IMAP search command). And, for IMAP folder views in Opera, the "search in mail" field could have an option to search on the server with the "text" (like 'entire message' rule) search key.