[BUG] Sidebar fails to load when active editor is a SAP ADT virtual document

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?

The Claude Code sidebar panel fails to load with the error: "An error occurred while loading view: claudeVSCodeSidebarSecondary"

This only happens when the active editor is a virtual document opened via the official "ABAP Development Tools for VS Code" extension (SAP ADT). The sidebar works correctly when the active workspace is a normal local folder.

What Should Happen?

The Claude Code sidebar panel should load and function correctly regardless of whether the active editor is a real filesystem document or a virtual document (e.g. one provided by the SAP ADT extension), similar to how GitHub Copilot Chat is able to read the content of ADT's virtual documents.

Error Messages/Logs

VS Code: 1.135.0
Claude Code extension: 2.1.250
OS: Windows_NT x64 10.0.26200
Related extensions: ABAP Development Tools for VS Code (SAP ADT), @github/copilot 1.0.81-0

Error shown in sidebar:
An error occurred while loading view: claudeVSCodeSidebarSecondary

Steps to reproduce:
1. Install and connect "ABAP Development Tools for VS Code" to an SAP system
2. Open an ABAP object via ADT (opens a virtual document with a path like /repotree-v1/<system>/System Library/.../<program>.prog.abap — not a real filesystem path)
3. Open the Claude Code sidebar panel
Result: sidebar immediately fails with the error above

Sidebar works fine when the active workspace is a normal local folder (tested with plain .sql files) — issue only reproduces with ADT's virtual document.
CLI (`claude` in integrated terminal) is unaffected and works normally.

Steps to Reproduce

1. Install the official "ABAP Development Tools for VS Code" extension and connect it to an SAP system
2. Open any ABAP object (e.g. a program) via the ADT explorer — this opens a virtual document with a path like /repotree-v1/<system>/System Library/.../<program>.prog.abap (not a real filesystem path)
3. Open the Claude Code sidebar panel while this virtual document is the active editor
4. Error appears immediately: "An error occurred while loading view: claudeVSCodeSidebarSecondary"

Note: The sidebar loads and works correctly when the active editor/workspace is a normal local folder — the issue only reproduces when working with ADT's virtual documents.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.250 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Company uses Team plan with premium seat. The workspace root folder in a normal scenario works fine with the sidebar — this issue is specifically tied to ADT's custom URI scheme (repotree-v1) for virtual documents, which likely isn't handled by the sidebar's file-reading logic the same way the CLI's file tools handle it.