Plasma via xrdp: keyboard layout issue

Describe the bug

Arrow keys (and some other keys) do not work in Plasma inside XRDP session. Specifically, in text fields entering "hello" and pressing Left Arrow does not move cursor to the left before 'o'. Down Arrow key seems to work as Enter.

Arrow keys work in XRDP, on the login screen Left Arrow does the right thing.

Steps To Reproduce

  # Enable the X11 windowing system.
  # services.xserver.enable = true; - tried to uncomment that as well
  services.displayManager.sddm.enable = true;
  services.displayManager.sddm.wayland.enable = true;
  services.desktopManager.plasma6.enable = true;

  services.xserver.xkb = { # removing and adding this whole section does not fix it
    layout = "us";
    variant = "";
    options = "grp:win_space_toggle";
  };

  services.xrdp.enable = true;
  services.xrdp.defaultWindowManager = "startplasma-wayland";
  services.xrdp.openFirewall = true;

The RDP into the system (I am using Windows client).

Expected behavior

Left Arrow key should move cursor to the left

Screenshots

Works here

Does not work here

Additional context

NixOS is installed in Hyper-V with GPU partitioning enabled, but AFAIK the driver for vGPU has not been set up, Plasma reports llvmpipe.

Notify maintainers

Metadata

Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

 - system: `"x86_64-linux"`
 - host os: `Linux 6.6.32, NixOS, 24.05 (Uakari), 24.05.1358.47b604b07d1e`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.18.2`
 - channels(root): `"nixos-24.05"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

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