On mobile, session sidebar stays open after selecting a session, hiding the session #37746

Description

Note: now the new tabbed UI has been rolled out, this is a fix for the non-tabbed UI which can be enabled in settings.

On narrow/mobile viewports, selecting a session from the session sidebar navigates to that session but leaves the sidebar open over the chat view.

This makes session switching feel stuck when the sidebar covers all of the screen: the selected session loads, but the user cannot see it or dismiss the sidebar, so it feels like it's stuck/trapped.

Similar reports have been provided by other users in issues and comments such as #24577 , #14711 , which were closed as stale, not as fixed.

I'm also submitting a PR paired to this issue with a proposed fix that preserves the current behavior on wider displays in which the user can click/tap outside the sidebar; and adds the fix for narrow displays where the sidebar takes all the screen width making it impossible for the user to tap the session.

Plugins

No plugins

OpenCode version

dev branch, OpenCode 1.18.3

Steps to reproduce

1. Start the web UI with opencode web or the local dev web UI.
2. Open it on a phone or narrow browser viewport.
3. Open a project with multiple sessions.
4. Open the session sidebar.
5. Tap an existing session.
6. Observe that the URL/session changes, but the sidebar remains open over the chat view, so the user feels stuck not being able to tap the session to dismiss the sidebar.

Screenshot and/or share link

No response

Operating System

Host: any, Client: mobile browser / narrow desktop browser viewport

Terminal

Not terminal-specific