[v2] fix: Files DragAndDrop bugs with OnDomReady and DisableWebViewDrop

[leaanthony]

Summary

Fixes #3563

This PR addresses two critical issues with file drag-and-drop functionality:

1. OnDomReady triggering on every drag-and-drop: When EnableFileDrop: true, dropping files would trigger OnDomReady multiple times because the browser's default behavior (navigating to the dropped file) wasn't prevented early enough.

2. EnableFileDrop + DisableWebViewDrop conflict: When both options were enabled together on Windows, file dropping stopped working entirely.

Root Cause

• JavaScript drag/drop event handlers that call e.preventDefault() were only registered when the user called runtime.OnFileDrop()
• There's a timing gap between page load and when OnFileDrop() is called (typically in the OnDomReady handler)
• During this gap, if a file is dropped, the browser's default behavior kicks in - navigating to the dropped file (file:///path/to/file.txt)
• This navigation triggers OnDomReady again

The Fix

1. Early handler registration (JavaScript)

• Added setup() function in draganddrop.js that registers drag/drop handlers immediately
• Called from main.js during runtime initialization (before runtime:ready)
• Handlers prevent default for file drops even before the user registers a callback
• Runs on every DOM load to ensure handlers are always registered

2. Windows AllowExternalDrag fix

• Only disable AllowExternalDrag when DisableWebViewDrop: true AND EnableFileDrop: false
• When both are true, drag events need to flow to JavaScript

Test plan

• [ ] Test drag-and-drop with EnableFileDrop: true - verify OnDomReady only fires once
• [ ] Test with both EnableFileDrop: true and DisableWebViewDrop: true on Windows
• [ ] Test on Linux and macOS to ensure no regressions
• [ ] Verify file drop callbacks still work correctly

🤖 Generated with Claude Code

[coderabbitai[bot]]

[!IMPORTANT]

Review skipped

Draft detected.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

✨ Finishing touches

🧪 Generate unit tests (beta)

• [ ] Create PR with unit tests
• [ ] Post copyable unit tests in a comment
• [ ] Commit unit tests in branch claude/investigate-fix-issue-01Er6YmLxZvbLYhZSQkJvjg7

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[cloudflare-workers-and-pages[bot]]

Deploying wails with    Cloudflare Pages

Latest commit:	ae04fea
Status:	✅  Deploy successful!
Preview URL:	https://2d7db912.wails.pages.dev
Branch Preview URL:	https://claude-investigate-fix-issue.wails.pages.dev

View logs