[Bug]: File picker not always on top

[lukasvida]

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a bug report that matches the one I want to file, without success.

Electron Version

30.0.1

What operating system are you using?

Other Linux

Operating System Version

Fedora Desktop 39

What arch are you using?

x64

Last Known Working Electron version

17.8.4

Expected Behavior

When i open Electron app in fullscreen mode and click on any filepicker used for input (i. e. input type file) a filepicker opens. When i click anywhere outside the filepicker, the filepicker stays always on top. However, when I click on any button that leads to opening the file picker used for download, the file picker opens, but when I click outside the file picker, the file picker disappears to background and the only way to get to file picker is alt+tab combination (because the application is run in fullscreen mode).

Actual Behavior

In both cases (input and download) the file picker should stay always on top.

Testcase Gist URL

https://gist.github.com/lukasvida/1805c9078efda7ef648d95de63757b24

Additional Information

This problem may be casued by #34774, maybe @miniak may add something to this.
When I run Electron from CLI and I click on the download button, this error appears in the terminal:

[5036:0419/061845.081380:ERROR:browser_main_loop.cc(280)] GLib-GObject: invalid cast from 'GtkFileChooserNative' to 'GtkWidget'