VS Code 1.143.0: Enabling chat.canvases causes Copilot harness to hang on Linux Ubuntu during prepareTurn with BYOK models

Does this issue occur when all MCP-servers disabled?: Yes Report Issue' dialog can assist with this. --> - VS Code Version: 1.143.0; 2d0b7506a36c1d6db9a466440131a8e01eab2289; x64 - OS Version: Ubuntu 26.04.1 LTS (Resolute Raccoon) x86_64 [Linux 7.0.0-38-generic] Steps to Reproduce: Set in .config/Code/User "chat.canvases.enabled": true To fix: Set in .config/Code/User "chat.canvases.enabled": false More context: - Model: glm-5.3-flash-llmlb, accessed through an OpenAI-compatible Open WebUI endpoint. - Local harness: Works correctly. - Copilot harness: Hangs with "This is taking a little longer than usual". - API verification: Both streaming and non-streaming requests succeed. - MCP servers and plugins: Disabling them does not resolve the issue. And here are some log excerpts: > [Copilot] Preparing SDK session: kind=create > [ByokLmProxyService] listening on http://127.0.0.1:36463 > [Copilot] Wired 1 BYOK model(s) across 1 provider(s) > [Copilot] Resolved system message > ... > [warning] Chat queue task stalled: operation=prepareTurn