feat: open .html files in built-in browser pane

[shreyaspapi]

Summary

Adds the ability to open local .html/.htm files in Emdash's built-in browser pane directly from the file explorer context menu. Also fixes a pre-existing bug where the browser pane's full-screen overlay blocked mouse events on the editor and sidebar.

Changes:

• FileTree.tsx: Added "Open in Browser Pane" context menu item for .html/.htm files. Uses useBrowser().open() to load a file:// URL in the built-in browser pane.
• BrowserPane.tsx: Moved pointer-events-auto from the full-screen outer wrapper to the inner pane div, so the editor and sidebar remain interactive when the browser pane is open. Also updated the address bar regex to accept file:// URLs without prepending http://.

Fixes

Fixes #1421

Snapshot

To be added

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Chore (refactoring code, technical debt, workflow improvements)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (does not change functionality, e.g. code style improvements, linting)
• This change requires a documentation update

Mandatory Tasks

• I have self-reviewed the code
• A decent size PR without self-review might be rejected

Checklist

• I have read the contributing guide
• My code follows the style guidelines of this project (pnpm run format)
• I have commented my code, particularly in hard-to-understand areas
• I have checked if my PR needs changes to the documentation
• I have checked if my changes generate no new warnings (pnpm run lint)
• I have added tests that prove my fix is effective or that my feature works
• I haven't checked if new and existing unit tests pass locally with my changes

[vercel]

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[greptile-apps]

Greptile Summary

This PR adds "Open in Browser Pane" to the file explorer context menu for .html/.htm files and fixes a pre-existing bug where the full-screen overlay wrapper was capturing mouse events even when the browser pane was closed. Both features are implemented cleanly. A new browserPaneUtils.ts module centralises URL-related logic (isHtmlFile, normalizeAddressBarUrl, buildFileUrl) and is covered by a dedicated test file.

Key changes:

• BrowserPane.tsx: pointer-events-auto is now correctly scoped to the inner pane <div> rather than the full-screen wrapper, so the editor and sidebar remain interactive when the pane is hidden.
• BrowserPane.tsx: Address-bar form submission delegates to normalizeAddressBarUrl, which now preserves file:// URLs in addition to http:///https://.
• FileTree.tsx: "Open in Browser Pane" context menu entry rendered for HTML files via isHtmlFile, properly guarded inside the node.type === 'file' branch; handleOpenInBrowser is memoised with useCallback.
• browserPaneUtils.ts: buildFileUrl has a Windows-compatibility bug — when rootPath has no leading / (e.g. C:/Users/...), the function emits file://C:/... instead of the required file:///C:/.... A one-line guard (absPath.startsWith('/') ? absPath : \/${absPath}``) would fix this. The test suite omits Windows-style path cases, so the bug goes undetected.

Confidence Score: 4/5

• Safe to merge for macOS/Linux users; one minor Windows path-formatting bug in buildFileUrl should be addressed before shipping on Windows.
• The logic for the pointer-events fix and the context menu feature is correct and well-structured. The only identified defect is in buildFileUrl: on Windows, the missing leading slash before a drive letter produces a malformed file://C:/... URL. Since the app appears to primarily target macOS (e.g. "Reveal in Finder"), this is low risk in practice but worth fixing before any Windows release.
• Pay close attention to src/renderer/lib/browserPaneUtils.ts (buildFileUrl) and its test file for the Windows path edge case.

Important Files Changed

Filename	Overview
src/renderer/lib/browserPaneUtils.ts	New utility module with three helpers. isHtmlFile and normalizeAddressBarUrl are correct and well-tested. buildFileUrl has a Windows path bug: omits the required third slash when rootPath doesn't start with / (e.g. C:/... on Windows), producing file://C:/... instead of file:///C:/....
src/renderer/components/BrowserPane.tsx	Two clean changes: (1) pointer-events-auto moved from the full-screen wrapper to the inner pane div, correctly fixing the mouse-event blocking bug; (2) inline address-bar URL normalisation replaced with the new normalizeAddressBarUrl utility, which also adds file:// support. Both changes are correct.
src/renderer/components/FileExplorer/FileTree.tsx	Adds "Open in Browser Pane" context menu item, correctly guarded by node.type === 'file' and isHtmlFile(node.name). The handleOpenInBrowser callback is properly memoised with useCallback. The callback delegates path building to buildFileUrl(rootPath, node.path), consistent with how other handlers join these two values.
src/test/renderer/browserPaneUtils.test.ts	Good coverage for isHtmlFile and normalizeAddressBarUrl. buildFileUrl tests only exercise Unix-style paths; no Windows-style drive-letter paths (e.g. C:/...) are tested, leaving the Windows bug undetected.

Sequence Diagram

sequenceDiagram
    participant User
    participant FileTree
    participant browserPaneUtils
    participant BrowserProvider
    participant BrowserPane
    participant ElectronAPI

    User->>FileTree: Right-click .html file
    FileTree->>FileTree: isHtmlFile(node.name) → show menu item
    User->>FileTree: Click "Open in Browser Pane"
    FileTree->>browserPaneUtils: buildFileUrl(rootPath, node.path)
    browserPaneUtils-->>FileTree: file:///root/path/to/file.html
    FileTree->>BrowserProvider: browser.open(fileUrl)
    BrowserProvider->>BrowserProvider: navigate(fileUrl) → setUrl(fileUrl)
    BrowserProvider->>ElectronAPI: browserLoadURL(fileUrl)
    BrowserProvider->>BrowserProvider: setOpen(true)
    BrowserPane->>BrowserPane: paneVisible=true, shouldShow=true
    BrowserPane->>ElectronAPI: browserShow(bounds, fileUrl)
    ElectronAPI-->>User: HTML file rendered in browser pane

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_{Last reviewed commit: 5043944}

[arnestrickmann]

Thanks! @shreyaspapi
Could you post a screen recording of the UX for this addition?

[shreyaspapi]

Thanks! @shreyaspapi Could you post a screen recording of the UX for this addition?

Screen.Recording.2026-03-13.at.12.24.28.PM.mov