The preview option was being ignored when using vscode.commands.executeCommand('vscode.openWith', uri, editorId, {preview: true}). This caused custom editors to always open in pinned mode (tab not italicized) instead of respecting the user's preview preference.

Problem

When calling:

vscode.commands.executeCommand('vscode.openWith', uri, 'hexEditor.hexedit', {preview: true});

The tab would always appear pinned (not italicized) instead of in preview mode (italicized), indicating that the preview: true option was being ignored.

Root Cause

In src/vs/workbench/browser/parts/editor/editorCommands.ts, the API_OPEN_WITH_EDITOR_COMMAND_ID command implementation had a hardcoded pinned: true that was overriding user preferences:

// Before fix
{ pinned: true, ...optionsArg, override: id }

Even though the user's {preview: true} gets correctly converted to {pinned: false} by the type converter, the hardcoded pinned: true was preventing this preference from being respected.

Solution

Removed the hardcoded pinned: true to allow user preferences to take precedence:

// After fix
{ ...optionsArg, override: id }

This makes the openWith command consistent with the regular open command, which doesn't have a hardcoded pinned value.

Testing

Added comprehensive unit tests in src/vs/workbench/test/browser/parts/editor/editorCommandsOpenWith.test.ts covering:

• Preview mode when preview: true is specified
• Pinned mode when preview: false is specified
• Default behavior when no options are provided

Impact

This fix ensures that:

• Extensions can properly control preview behavior for custom editors
• User preferences are respected consistently across all editor opening commands
• The behavior matches user expectations as described in the original issue

The change is minimal and surgical, affecting only the specific problematic code path without impacting other functionality.

Fixes #235535.

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.