[BUG] File Pane can't open files in a secondary/added folder — "outside the session folder" in multi-folder sessions

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?

In a Claude Code Desktop session with more than one project folder added (a multi-root session), the File Pane cannot open files that live in any folder other than the primary one.

Clicking a file link in the chat that points into a secondary added folder shows:

File could not be read. It may have been deleted or moved, or it lives outside the session folder.

This happens even though:

• The file exists on disk.
• The secondary folder is a fully tracked part of the session — it has its own diff / "Commit changes" control in the composer, with a real pending-change count.
• The path is plain ASCII, so this is not the Unicode-normalization variant in #51584.
• Claude's own Read/Write tools open and edit these same files correctly in the same session; only the File Pane preview fails.

The File Pane appears to resolve file links against a single "session folder" (the primary one) and treats anything under a secondary added folder as outside the session, instead of resolving against all folders attached to the session.

What Should Happen?

Clicking a file link that points into any folder attached to the session — including secondary/added folders — should open that file in the File Pane.

File-link path resolution should consider the full set of working folders in the session, not just the primary one. The app already treats the secondary folder as a working folder elsewhere (it shows that folder's diffs and a "Commit changes" control), so the File Pane should honor it too.

Error Messages/Logs

File Pane:
File could not be read. It may have been deleted or moved, or it lives outside the session folder.

No console errors observed in the UI. Happy to add logs if there's a specific place to look.

Steps to Reproduce

1. Open Claude Code Desktop.
2. Create two throwaway folders, each with one file:

• project-primary/hello.txt
• project-secondary/world.txt

1. Start a session and add BOTH folders. Each shows its own "Commit changes" control in the composer.
2. Ask Claude to add a comment line to the top of project-secondary/world.txt. After the edit, the file path becomes a clickable link in the chat.
3. Click that link (the one pointing into project-secondary/).

Result: the File Pane shows "File could not be read … outside the session folder."
A link pointing into project-primary/ opens correctly in the same session — only the secondary-folder link fails.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude 1.10628.2 (deee0a) 2026-06-03T20:08:36.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

This is the Claude Code Desktop GUI (the File Pane / file-preview pane), not the CLI — suggest the area:desktop label.

Possibly related path-resolution issues in the same File Pane layer (different root causes — please open each link to verify before relying on them):

• #51584 — non-ASCII / Unicode NFC-NFD path bug
• #61443 — Windows drive-letter / slash normalization
• #51331 — SSH sessions

This report is specifically about multi-folder / multi-root sessions.

Workaround: copy the file path manually into the OS file manager or an IDE.