[Bug]: A maximized right panel comes back un-maximized after visiting Settings or another thread #17326

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/web

Steps to reproduce

A thread used as a full-window preview loses its maximized layout when you leave it and come back.

1. Open a thread and open the browser preview in the right panel.
2. Click Maximize panel in the panel header. The chat column collapses.
3. Open Settings, then click the thread in the sidebar.

A second path: at step 3, open another thread instead, maximize its right panel, then click the first thread.

Expected behavior

The first thread's panel is still maximized. Only Restore panel size or closing the panel should un-maximize it.

Actual behavior

The chat column is back beside the panel.

ChatView.tsx:1915 keeps the flag in component state that holds one thread key:

const [maximizedRightPanelThreadKey, setMaximizedRightPanelThreadKey] = useState<string | null>(null);

The rest of the panel's state (open, tabs, active tab) is saved per thread in rightPanelStore. Three things drop the flag:

• _chat.tsx:227 renders <Outlet /> in place of ThreadRouteView on any non-thread route, so visiting Settings unmounts ChatView.
• ThreadRouteView.tsx:171 keys each draft's ChatView separately, so opening a new thread mounts a fresh instance.
• Maximizing a second thread's panel overwrites the single stored key.

Impact

Minor bug or occasional failure

Version or commit

main @ 5809487

Environment

macOS (Darwin 27.0.0), T3 Code desktop

Screenshots, recordings, or supporting files

Recorded on main @ 5809487 with sample data: before.mp4

Workaround

Click Maximize panel again after returning to the thread.

Related

Discussion #16893 asks for the flag to survive an explicit close and reopen. This report covers the case where the user never closes the panel.