Directory selection not possible on Linux (NixOS unstable with GNOME)

[das-g]

To reproduce:

1. go to https://github.com/Git-it-App/git-it-electron
2. click on the latest release in the section on the right (currently v5.2.2 based on a50f82f87d24ae67dd21b95ac40895de2f3f2b50)
3. download Git-it-linux-x64.zip
4. unpack the zip archive
5. open a terminal in the directory Git-it-linux-x64 created by that unzipping, or cd there in an already open terminal window
6. run

   NIXPKGS_ALLOW_UNFREE=1 nix run --impure nixpkgs#steam-run -- ./Git-it

7. in the Git-it app, click on the circle of the second challenge "repository"
8. scroll down to bring the blue "Please select your repository directory." box into view
9. in that box, click the button "Select directory"

expected

• a directory choosing dialog appears and a directory can be selected there

(This is also what happens when trying this with https://github.com/jlord/git-it-electron/releases/tag/4.4.0 instead.)

observed

• no directory choosing dialog appears
  • sometimes a window quickly appears and instantaneously vanishes again. Too quick (just flashing for much less than a second, maybe just a single frame) to make out what its contents would be.
• on the command line output (which until then was just

  [84093:0613/163148.713087:ERROR:sandbox_linux.cc(374)] InitializeSandbox() called with multiple threads in process gpu-process.

  a new line

  [84057:0613/163620.047068:ERROR:browser_main_loop.cc(269)] Gtk: gtk_native_dialog_run: assertion '!priv->visible' failed

  appears just when the button was clicked.

Output of nix-info -m

• system: "x86_64-linux"
• host os: Linux 6.1.91, NixOS, 24.11 (Vicuña), 24.11.20240524.bfb7a88
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.18.2
• channels(das-g): ""
• channels(root): "nixos"
• nixpkgs: /nix/store/z71lmgd0ydfnax1b13zbrls5idf1y7ak-source