Fluxer flatpak and appimage desktop window missing shadow

$ flatpak info app.fluxer.Fluxer

Fluxer - Instant messaging and VoIP application

          ID: app.fluxer.Fluxer
         Ref: app/app.fluxer.Fluxer/x86_64/stable
        Arch: x86_64
      Branch: stable
     Version: 0.0.8
     License: AGPL-3.0-or-later
      Origin: flathub
  Collection: org.flathub.Stable
Installation: system
   Installed: 321.4?MB
     Runtime: org.freedesktop.Platform/x86_64/25.08
         Sdk: org.freedesktop.Sdk/x86_64/25.08

      Commit: 21097fb218e7edcdbb9e1d6832abc086a366518802fd9f2a2b59acb44372c5c3
      Parent: c322992ec132079a1675467f48ceea97cba79fbe65ae38ccfb3688b0f20c4432
     Subject: Delete flathub.json (badafc4563cb)
        Date: 2026-03-19 02:18:53 +0000

$ gnome-shell --version
GNOME Shell 49.5

$ echo $XDG_SESSION_TYPE
wayland

$ uname -srvmo
Linux 6.19.9-arch1-1 #1 SMP PREEMPT_DYNAMIC Thu, 19 Mar 2026 16:33:17 +0000 x86_64 GNU/Linux

$ head -n1 /etc/os-release 
NAME="Arch Linux"

$ flatpak run app.fluxer.Fluxer
[2:0325/102713.204309:ERROR:dbus/bus.cc:406] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
10:27:13.486 › Configured user data storage {
  channel: 'stable',
  directory: 'fluxer',
  path: '/home/tgf9/.var/app/app.fluxer.Fluxer/config/fluxer'
}
[2:0325/102713.591429:ERROR:dbus/bus.cc:406] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
[2:0325/102713.591487:ERROR:dbus/bus.cc:406] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
10:27:13.603 › App ready, initializing...
LaunchProcess: failed to execvp:
xdg-settings
10:27:13.608 › Restored window bounds: { x: 0, y: 0, width: 1424, height: 955, isMaximized: false }
10:27:13.637 › Electron's autoUpdater does not support the 'linux' platform. Ref: https://www.electronjs.org/docs/latest/api/auto-updater#platform-notices
10:27:13.642 › App initialized successfully
10:27:13.650 › [RPC] Server listening on http://127.0.0.1:21863
[57:0325/102713.711372:ERROR:ui/ozone/platform/wayland/gpu/wayland_surface_factory.cc:251] '--ozone-platform=wayland' is not compatible with Vulkan. Consider switching to '--ozone-platform=x11' or disabling Vulkan
10:27:14.066 › [Window] Failed to load app URL: Error: ERR_ABORTED (-3) loading 'https://web.fluxer.app/channels/@me'
    at rejectAndCleanup (node:electron/js2c/browser_init:2:83298)
    at WebContents.navigationListener (node:electron/js2c/browser_init:2:83578)
    at WebContents.emit (node:events:508:28)

$ ./fluxer-stable-0.0.8-x86_64.AppImage 
10:35:14.627 › Configured user data storage {
  channel: 'stable',
  directory: 'fluxer',
  path: '/home/tgf9/.config/fluxer'
}
10:35:15.231 › App ready, initializing...
10:35:15.249 › Restored window bounds: { x: 0, y: 0, width: 1920, height: 1168, isMaximized: true }
10:35:15.787 › Electron's autoUpdater does not support the 'linux' platform. Ref: https://www.electronjs.org/docs/latest/api/auto-updater#platform-notices
10:35:15.804 › App initialized successfully
10:35:15.815 › [RPC] Server listening on http://127.0.0.1:21863
10:35:15.816 › [WS Proxy] Server listening on ws://127.0.0.1:21865
10:35:15.816 › [API Proxy] Server listening on http://127.0.0.1:21861/proxy
10:35:15.817 › [Media Proxy] Server listening on http://127.0.0.1:21867/media
10:35:15.826 › Saved window bounds: { x: 0, y: 0, width: 1920, height: 1168, isMaximized: false }
10:35:15.831 › Saved window bounds: { x: 0, y: 0, width: 1920, height: 1168, isMaximized: true }
Failed to load app URL: Error: ERR_ABORTED (-3) loading 'https://web.fluxer.app/channels/@me'
    at rejectAndCleanup (node:electron/js2c/browser_init:2:79946)
    at WebContents.navigationListener (node:electron/js2c/browser_init:2:80226)
    at WebContents.emit (node:events:519:28) {
  errno: -3,
  code: 'ERR_ABORTED',
  url: 'https://web.fluxer.app/channels/@me'
}
10:35:23.484 › Saved window bounds: { x: 0, y: 0, width: 1920, height: 1168, isMaximized: false }
10:35:26.196 › Saved window bounds: { x: 0, y: 0, width: 1920, height: 1168, isMaximized: true }
10:35:28.120 › Saved window bounds: { x: 0, y: 0, width: 1920, height: 1168, isMaximized: false }
10:35:28.627 › Saved window bounds: { x: 0, y: 0, width: 1717, height: 1044, isMaximized: false }
10:35:32.979 › Saved window bounds: { x: 0, y: 0, width: 941, height: 664, isMaximized: false }
10:36:57.650 › Saved window bounds: { x: 0, y: 0, width: 941, height: 664, isMaximized: false }