I'm in the process to update my project https://github.com/markusdd/EasyEDA_to_KiCAD_Lib_UI from egui 0.26.2 to 0.29.1 and I am facing a problem with a feature I previously used.
I have a set of thumbnail pictures for electronic parts:

These can be hovered, and this will cause a big version of the picture to be displayed. As the resulting overlay window is non-interactive, click and hover actions used to be transferred to the layer below, the resulting picture was stable until you moved the mouse outside the underlying thumbnail area. Exactly what I wanted.

ui.horizontal(|ui| {
                    for url in imagevec {
                        let img = ui
                            .add(egui::Image::new(url).fit_to_exact_size(Vec2::new(200.0, 200.0)));
                        if img.hovered() {
                            Window::new("")
                                .auto_sized()
                                .interactable(false)
                                .show(ctx, |ui| {
                                    ui.add(
                                        egui::Image::new(url)
                                            .fit_to_exact_size(Vec2::new(900.0, 900.0)),
                                    );
                                });
                        }
                    }
                });

Wanted result (works in egui 0.26.2):

Now, in 0.29.1, I get a semi-transparent big overlay picture window. Until I realized I cannot screenshot the problem and it's not actually transparent.
With each frame, the window appears and disappears, causing essentially 50% translucency to the human eye.

So my assumption is, that hover events no longer properly pass through non-interactive windows like they used to.

How to solve for this?

I tried to set fade_in/out to false, I tried different orders like popup, foreground etc, all does not help.

Any advice? is this intended or a bug? Any new paradigm to get this feature back?