In Gmail (and Outlook), each row of the message list shows the sender, the subject and the first words of the message. Those first words are often useful: at a glance, they give you a better idea of what the message is about.
In Proton webmail, the list has no preview, so I have to open messages to find out.

I understand why Proton can't do it like Gmail: messages are only decrypted in the browser, when you open them.
But with content search enabled, the content is already decrypted on the computer: the search index stores the plain-text body of each message, and the web app keeps a decrypted copy of it in memory. The row layout even renders a body excerpt already, but only for search results.

So for these users, a one-line preview would just be a local lookup: no extra download, no extra decryption, no change to the privacy model.

Suggestion:
- An opt-in setting "Show message preview in the list", available when content search is enabled.
- Row layout: grey preview text after the subject (Column layout: one line under it).
- No preview for messages not (yet) in the index.

(Code pointers, public WebClients repo: ItemRowLayout.tsx and packages/encrypted-search/lib/models/interfaces.ts)