[Bug]: File upload with drag & drop not working (randomly) on GNOME with Wayland

[leoniscsem]

Checks before filing an issue

• This issue doesn't reproduce on web browsers (such as in Chrome). If it does, issue reports go to the Mattermost Server repository.
• I have checked the issue tracker and have not found an issue that matches the one I'm filing.
• This issue is not a troubleshooting question. Troubleshooting questions go here: https://forum.mattermost.com/c/trouble-shoot/16.
• This issue is not a feature request. You can request features and make product suggestions here: https://mattermost.com/suggestions/.
• This issue reproduces on the most recent stable version, or the most recent prerelease version of the Mattermost Desktop App.
• I have read the contribution guidelines.

Mattermost Desktop Version

5.10.2 commit de876ca (snap installation)

Operating System

Ubuntu Linux 22.04 LTS x64, GNOME 42.9 with Wayland

Mattermost Server Version

10.3.1 (deb installation)

Steps to reproduce

1. have a GNOME session with Wayland window manager
2. go to any channel
3. drag and drop a file from file manager

Expected behavior

After dragging a file to the main window of Mattermost, the background should go black and show the "drop file here to upload" dialogue. After releasing the file, it should be uploaded.

Observed behavior

The behaviour is not consistent. Sometimes it works on the first try. The second try then usually does not work, no dark background / upload message.
Sometimes wiggling the file while hovering over the main channel triggers the dark upload background, sometimes not.
Sometimes it results to an error message "file cannot be uploaded".
Not dropping the file when no upload dialogue appears and re-grabbing it, then trying to drop it again sometimes yields results.

Log Output

no relevant output from main.log, only this (log level debug)

[2024-12-23 16:58:24.307] [debug] [MainWindow] saving window state {
  x: 1920,
  y: 0,
  width: 1920,
  height: 1080,
  maximized: true,
  fullscreen: false
}
[2024-12-23 16:58:36.897] [debug] [ViewManager] handleSetCurrentViewBounds { x: 1920, y: 0, width: 1920, height: 1080 }
[2024-12-23 16:58:36.899] [debug] [ModalManager] handleResizeModal {
  bounds: { x: 1920, y: 0, width: 1920, height: 1080 },
  modalQueueLength: 0
}
[2024-12-23 16:58:36.902] [debug] [ViewManager] focusCurrentView
[2024-12-23 16:58:40.262] [debug] [ViewManager] handleSetCurrentViewBounds { x: 1920, y: 0, width: 1920, height: 1080 }
[2024-12-23 16:58:40.264] [debug] [ModalManager] handleResizeModal {
  bounds: { x: 1920, y: 0, width: 1920, height: 1080 },
  modalQueueLength: 0
}
[2024-12-23 16:58:40.265] [debug] [MainWindow] saving window state {
  x: 1920,
  y: 0,
  width: 1920,
  height: 1080,
  maximized: true,
  fullscreen: false
}

Additional Information

The upload dialogue seems to be triggered randomly. I have tested the file upload functionality on Firefox 133.0.3 (deb) and Chomium 131.0.6778.139 (snap). My assumption is the issue is related to either the xwayland package (2:22.1.1-1ubuntu0.14), or Google's Wayland interpreter for Electron apps.

I do not face this issue when loading an X-server session for GNOME.