Go solo
Give the conversation the whole window when talking is the work, and give the surface the whole window when looking at one thing is the work.
What you'll have
A channel showing one column at full width — the conversation or the surface — and back to two columns in one gesture.
Select Show the conversation on its own in the conversation pane’s own header, at the right of the strip headed Conversation. Use it when talking is the work — a planning discussion, a design call, reading back what happened while you were away.
Result The surface steps aside and the conversation fills the window. The header widens with it: the channel name, its state, its pull request (PR) badge and its one-line description sit on one line, and a folded run of agent updates shows as a single row.
To give the surface the window instead, select Collapse the conversation beside it, or Hide the conversation in the surface pane’s own header. Use it when inspection is the work — a long diff, a live shell, a dashboard during an incident.
Result The surface takes the full width. The surface fills the available width while the conversation stays out of view.
For anything between the two, drag the divider between the columns. The conversation column resizes rather than disappears, which is what you want when you are reading a diff and answering questions about it at the same time.
Result The two columns settle where you left them, and both stay on screen.
From a full-width conversation, select Show the surface beside the conversation — the same control, which now reads the other way. From a full-width surface, select Show the conversation in the surface pane’s header.
Result Both columns are back, and the conversation is where it was.
If this doesn't work
The available controls depend on which panes are open and the window width. If a pane has no layout control, confirm that another pane is open and try a wider window. If the conversation comes back with messages you had not seen, that is the record catching you up rather than anything reordering itself, and A message is missing from a channel covers the opposite case.
The channel gives one column the whole width, and each pane’s own header carries the control that gives it back.