wails/DND_ISSUES.md

Wails Drag and Drop Issues Report

Summary

This report compiles all drag and drop related issues found in Wails v3 GitHub repository. The issues span across multiple platforms (Windows, macOS, Linux) and various versions of Wails.

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Issue #1: [V3] Drag-and-drop broken on Windows since alpha 19

Title: [V3] Drag-and-drop broken on windows since alpha 19
Platform: Windows 10
Reported: 2024-08-09
Location: GitHub
Reporter: xob0t
Link: https://github.com/wailsapp/wails/issues/4489

Summary: No drag and drop events are triggered on the Go side in Wails v3 alpha 20+. The issue appears to have been introduced by PR #4318.

Reproduction:

1. Run dnd example on Windows
2. Observe that no DnD events are triggered

System: Windows 10 Pro, Wails v3.0.0-alpha.20, AMD Ryzen 5 5600X, NVIDIA GeForce RTX 3070

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Issue #2: Windows 10 doesn't receive drag and drop events on the backend

Title: Windows 10 doesn't receive drag and drop events on the backend
Platform: Windows 10
Reported: 2025-01-07
Location: GitHub
Reporter: makew0rld
Link: https://github.com/wailsapp/wails/issues/3985

Summary: Backend drop handler registered with runtime.OnFileDrop never gets executed when dropping files on Windows 10, though JavaScript drop events do fire. The event is not being propagated to the backend properly.

Reproduction:

1. Clone https://github.com/makew0rld/wails-issue-3985
2. Build for Windows: wails build -platform windows/amd64 -windowsconsole -debug
3. Open the .exe in Windows
4. Open web console using right-click menu
5. Drag in a file
6. Observe nothing appears in backend console, but drop event appears in web console

System: Built on Arch Linux, tested on Windows 10 VM, Wails v2.9.2

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Issue #3: [v3] [mac] drag n drop does not work as expected after resizing window

Title: [v3] [mac] drag n drop does not work as expected after resizing window
Platform: macOS
Reported: 2024-09-12
Location: GitHub
Reporter: Etesam913
Link: https://github.com/wailsapp/wails/issues/3743

Summary: On macOS, after resizing the window, drag and drop usually gets rejected when trying to drag a file into the window.

Reproduction:

1. git checkout v3-alpha
2. cd v3/examples/drag-n-drop
3. go run main.go
4. Resize window
5. Drag file into window
6. File gets rejected

System: macOS 15.0, Apple M2, Wails v3.0.0-alpha.6

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Issue #4: Webview failed to set AllowExternalDrag to false on Win 10

Title: Webview failed to set AllowExternalDrag to false on Win 10 (after cross compile on macOS)
Platform: Windows 10
Reported: 2024-09-26
Location: GitHub
Reporter: barats
Link: https://github.com/wailsapp/wails/issues/3782

Summary: Two main issues: 1) WebView fails to set AllowExternalDrag to false, causing WebView to automatically open dragged files. 2) Backend runtime.OnFileDrop doesn't work - no events are triggered.

Reproduction:

1. Build windows/amd64 app on macOS
2. Move .exe files to Win10 and run
3. Drag and drop files into app window
4. WebView DnD not disabled, backend events not called

System: Built on macOS 15.0, tested on Windows 10, Wails v2.9.2

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Issue #5: [v2] Files DragAndDrop bugs

Title: [v2] Files DragAndDrop bugs
Platform: Linux (Ubuntu)
Reported: 2024-06-23
Location: GitHub
Reporter: Vovan-VE
Link: https://github.com/wailsapp/wails/issues/3563

Summary: Two issues: 1) When only EnableFileDrop: true, every D'n'D triggers an OnDomReady event. 2) When EnableFileDrop: true, DisableWebViewDrop: true, D'n'D doesn't work at all for files.

Reproduction:

func (a *App) domReady(ctx context.Context) {
    runtime.OnFileDropOff(ctx)
    runtime.LogInfof(ctx, "DOM READY -------------------------------\n%+v", errors.New("WTF?"))
    runtime.OnFileDrop(ctx, a.onFileDrop)
}

func (a *App) onFileDrop(x, y int, paths []string) {
    runtime.LogInfof(a.ctx, "drop files: %#v\n%+v", paths, errors.New("WTF?"))
}

System: Ubuntu 22.04, AMD Ryzen 9 7950X, Wails v2.9.1 and v2.9.2

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Issue #6: File drag and drop displays file in Linux WebKit

Title: File drag and drop displays file in Linux WebKit
Platform: Linux
Reported: 2024-08-17
Location: GitHub
Reporter: makew0rld
Link: https://github.com/wailsapp/wails/issues/3686

Summary: When dragging and dropping a file onto the Window, the OnFileDrop handler runs successfully, but the entire GUI is replaced with a view of the file if the browser supports it (e.g., images, PDFs). This makes the dropped file unusable as all UI is gone.

Reproduction:

1. Enable file dropping and add a simple handler
2. Try and drop an image file with WebKit on Linux
3. Observe the UI get replaced with a view of the image

System: Arch Linux, Intel Core i7-1165G7, Wails v2.9.1

Note: Issue was closed on 2025-08-02 with a workaround involving preventDefault() on drop and dragover events.

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Issue #7: Drag And Drop "wails-drop-target-active" class issue

Title: Drag And Drop "wails-drop-target-active" class is only applied if cssDropProperty is set via raw style
Platform: Windows
Reported: 2025-07-13
Location: GitHub
Reporter: riannucci
Link: https://github.com/wailsapp/wails/issues/4419

Summary: OnFileDrop does not apply the wails-drop-target-active class unless --wails-drop-target: drop is set directly via the element's style attribute, even though the OnFileDrop callback does fire.

Reproduction:

1. Set up a new wails project
2. Set EnableFileDrop in Application Options
3. Add CSS with --wails-drop-target: drop in stylesheet
4. Run app and drag file to target element
5. Base path gets set but element doesn't change styles

System: Windows 10/11 Pro, AMD Ryzen 7 5800X3D, Wails v2.10.2

Note: Issue was closed on 2025-08-02. Problem was in draganddrop.js using element.style instead of getComputedStyle.

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Issue #8: Use a user-agent that is more recognizable by front-end code

Title: Use a user-agent that is more recognizable by front-end code
Platform: macOS
Reported: 2024-01-31
Location: GitHub
Reporter: hsiafan
Link: https://github.com/wailsapp/wails/issues/3226

Summary: SortableJS (drag-and-drop library) doesn't work properly in Wails' webview because the userAgent doesn't contain standard browser identifiers like 'Safari/605.1.15', causing library detection to fail.

Reproduction: Libraries like SortableJS check userAgent for specific strings ('Edge', 'Firefox', 'Chrome', 'Safari') and fail to work properly when these are not present.

System: macOS, affects drag-and-drop libraries

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Issue #9: Application soft crashes when using vue-virtual-scroller on Linux

Title: Application soft crashes when using vue-virtual-scroller on Linux
Platform: Linux (Ubuntu)
Reported: 2024-10-22
Location: GitHub
Reporter: ysmilda
Link: https://github.com/wailsapp/wails/issues/3849

Summary: Using vue-virtual-scroller component causes the application to crash on Linux builds, rendering a grey screen and hanging the inspector window. Works fine on Windows and in dev view.

Reproduction:

1. Create new wails instance with wails init -n myproject -t vue-ts
2. Add vue-virtual-scroller component
3. Create Linux build (wails build -tags webkit2_41)
4. Observe crash while rendering

System: Ubuntu 24.04, Intel Core i7-12700, Wails v2.9.2

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Issue #10: [DragAndDrop] panic when dropping non-file objects

Title: [DragAndDrop] panic when dropping non-file objects
Platform: Windows
Reported: 2024-07-09
Location: GitHub
Reporter: Alpa-1
Link: https://github.com/wailsapp/wails/issues/3596

Summary: A panic occurs when dropping non-file objects (like strings or browser tabs) into the webview. The application crashes with a nil pointer dereference.

Reproduction:

1. Enable DragAndDrop
2. Add a drop target on frontend with --wails-drop-target
3. Register a callback with OnFileDrop((x,y,f) => { console.log(f) }, true)
4. Drop a Browser Tab onto the element
5. Application panics

System: Windows 10 Enterprise, AMD Ryzen 7 PRO 4750U, Wails v2.9.1

Note: Issue was closed on 2024-08-18. A simple nil check fix was provided.

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Common Patterns Identified:

1. Platform-specific issues: Windows has the most reported issues, particularly with events not reaching the backend
2. Version regression: Multiple reports indicate v3 alpha 19+ broke drag and drop on Windows
3. WebView configuration: Several issues relate to DisableWebViewDrop not working correctly
4. Cross-platform builds: Issues when building for Windows on other platforms
5. Frontend/Backend disconnect: Common pattern of JavaScript events firing but Go handlers not receiving events
6. UI replacement on Linux: Specific issue where dropped files replace the entire UI in WebKit

Recommendations:

1. Focus on Windows platform issues first as they are most prevalent
2. Investigate the changes in PR #4318 which allegedly broke Windows DnD
3. Review the event propagation mechanism between frontend and backend
4. Test cross-platform builds more thoroughly
5. Improve documentation on DragAndDrop configuration options