Looking for an example how to open multiple files at once

I'm looking for a minimal example showing how to open multiple files.


Here is what I tried unsuccessfully.
```rust
commands::SHOW_OPEN_PANEL.with(
 FileDialogOptions::new()
 .multi_selection()
 .button_text("Open"),
)
```

but it's not triggering `commands::OPEN_FILES`. It keeps triggering `commands::OPEN_FILE` even if I select multiple files.