Setting current-index on ComboBox does not work in some situations

[npwoods]

Bug Description

bug-demo.zip

In the attached example, main.slint looks like this:

import { ComboBox } from "std-widgets.slint";

export component AppWindow inherits Window {
    in property <[string]> combobox-model;
    in-out property <int> combobox-index <=> my-combobox.current-index;
    my-combobox := ComboBox {
        model: root.combobox-model;
    }
}

src/main.rs:

fn main() {
    let app_window = AppWindow::new().unwrap();

    let items = [
        "not this1",
        "not this2",
        "!!!THIS!!!",
        "not this3",
        "not this4",
    ];
    let model = VecModel::from_iter(items.iter().copied().map(SharedString::from));
    let model = ModelRc::new(model);
    app_window.set_combobox_model(model);
    app_window.set_combobox_index(2);
    app_window.run().unwrap();
}

I would expect this to result in a ComboBox with !!!THIS!!! selected. But it seems to not stick. Curiously, if we don't specify the model and put the ComboBox items directly in main.slint, this works

Reproducible Code (if applicable)

Environment Details

• Slint Version: 1.9.2
• Platform/OS: Windows
• Programming Language: Rust

Product Impact

No response

[hunger]

Thank you for reporting your problem.

This might be related to #6619, which is about the ComboBox showing the wrong item. I do not think it is the same issue though.