Reading pane option?

I’m not sure if this is the right category for this.

I was chatting with a friend about his dream of how the Discourse interface would look and he came up with something that almost looked like an email client with the messages on the left and a reading pane on the right. Similar to these in Fastmail and Gmail:

As I described Discourse to him as more closely resembling email / mailing interaction than text / chat messages, I wondered why the reading pane design didn’t seem to exist as it seems to be quite popular in email clients.

Has this been discussed before? Do others currently want something like this? Any guess at how easy/hard this would be to implement in a theme/component?


This is similar to the “Master - Detail” pattern for foldable devices: