Ungrouped sessions disappear from sidebar after creating a custom group

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

After creating a new custom sidebar group and moving one session into it, the "Sessions" (Ungrouped) section of the Code tab sidebar stops listing the rest of my existing sessions. It reports 0 sessions in that section even though ~10 other local sessions still exist, are not archived, and have group: null.

I verified this via the sidebar/session management tools:

• list_sessions confirms 10 sessions with group: null, isArchived: false.
• list_sections reports session_count: 0 for the built-in "sessions" (Ungrouped) section, regardless of filter state.
• Clearing all filters (status: "all", last_activity: 0) did not change the count.
• Toggling the sidebar's group_by between custom and none and back did not change the count.
• Fully restarting the desktop app did not fix it.
• Sidebar is not collapsed (sidebar_collapsed: false).

Related (not duplicate): #97658 (custom groups exist in data but don't render — cross-device sync) and #90648 (creating a manual group silently flips Group by mode). This report is specifically about the Ungrouped bucket losing its sessions on the same device, same session, right after a group is created.

What Should Happen?

The custom group section shows its own sessions, and the "Sessions" (Ungrouped) section continues to list every other existing session that isn't assigned to a group — exactly as it did before the group was created.

Error Messages/Logs

Steps to Reproduce

1. Have several existing local Code-tab sessions, none assigned to a custom group (group: null).
2. Create a new custom sidebar group (e.g. via the "+" / New Group action) and move one existing session into it.
3. Look at the sidebar: the new group section renders correctly with its session.
4. Look at the "Sessions" (Ungrouped) section: it shows 0 sessions, even though ~10 other sessions still exist with group: null and isArchived: false.

Already tried, none of which fixed it:

• Cleared sidebar filters (status: "all", last_activity: 0 / no limit).
• Toggled sidebar grouping mode between "custom" and "none" and back to "custom".
• Fully restarted the desktop app.
• Confirmed the sidebar itself is not collapsed.

The missing sessions are still reachable individually via their direct session link, so no data is lost — this is purely a sidebar listing/render bug.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Desktop app 2.26454.0 (98e3cc), built 2026-10-06T05:51:15.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

Diagnosed with the ccd_sidebar MCP tools (list_groups, list_sections, list_sessions, set_view) exposed to Claude in the Code tab:

• list_groups: 1 custom group "DANANANROD" with 1 session.
• list_sessions: 10 sessions with group: null, isArchived: false, not shown in sidebar.
• list_sections: "sessions" (Ungrouped) section reports session_count: 0, unaffected by clearing status/last_activity filters or toggling group_by.

Related issues (not duplicates): #97658, #90648.