Dragging does not work in a VSCode extension WebView

[wchengk09]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: Version: 1.96.3 (user setup) Commit: 91fbdddc47bc9c09064bf7acf133d22631cbf083 Date: 2025-01-09T18:14:09.060Z Electron: 32.2.6 ElectronBuildId: 10629634 Chromium: 128.0.6613.186 Node.js: 20.18.1 V8: 12.8.374.38-electron.0
• OS Version: Windows 11 Professional x64 22631.4602

Steps to Reproduce:

1. Clone https://github.com/wchengk09/vscode-webview-dragging-does-not-work
2. Open it in VSCode
3. Press F5 to run the extension

I want to create a WebView to add files by dragging it from the explorer to the WebView. But when I drag a file, VSCode will open it in a new editor, and the dragging event will not be caught. I also tried dragging files from the Windows explorer, and the result is the same. I even tried pressing shift when dragging the file, but I still cannot catch the event. I found some similar issues, such as #182449 and #218626, but none of them helped me.

Here is a video:

https://github.com/user-attachments/assets/acaf2051-4162-42bc-b7c6-d3101df17f31