Remove_item not working in Qt

Hello

I'm trying to delete all the buttons and labels from a layout and afterwards I delete the layout as well. This to add a new layout with other buttons and labels.

This is the relevant code (executed after button click):

        //DELETING all buttons, labels,...
        while self.widget.layout().count() > 0 {
            self.widget.layout().remove_item(
                self.widget.layout().item_at(0)
            );
                

            println!("{}", "Deleted something...");
        }
        //ATTEMPTS to delete the layout:
        //self.widget.as_mut_raw_ref().unwrap().layout().delete_later();
        //self.widget.layout().delete_later();
        //std::mem::drop(self.widget.as_mut_raw_ref().unwrap().layout());
        //std::mem::drop(self.widget.layout());
        //self.widget.layout().delete();
        //self.widget.as_mut_raw_ref().unwrap().layout().delete();
        //self.widget.layout().as_ref().unwrap().delete();
        
        //self.widget.[...].layout().as_ref().unwrap().delete()
        //self.widget.layout().as_ref().unwrap().delete()
        self.widget.as_mut_raw_ref().unwrap().layout().as_ref().unwrap().delete();
    

        //Building new layout etc
        let layout = QVBoxLayout::new_1a(&self.widget);

        //Label
        let label = QLabel::new();
        label.set_text(&qs("Label B!"));
        layout.add_widget(&label);
        
        //self.widget.as_mut_raw_ref().unwrap().set_layout(&layout);

It is compiling, and when I click the button Label B is added. But the problem is that the other labels and buttons are also still visible...

Full code & Cargo.toml:

#![windows_subsystem = "windows"]

//Importing the required stuff
use cpp_core::{Ptr, Ref, StaticUpcast, CppDeletable};
use qt_core::{qs, slot, ContextMenuPolicy, QBox, QObject, QPoint, SlotNoArgs, QString};
use qt_widgets::{
    QAction, QApplication, QLineEdit, QMenu, QMessageBox, QPushButton, QLabel, QTableWidget,
    QTableWidgetItem, QVBoxLayout, QWidget, SlotOfQPoint, SlotOfQTableWidgetItemQTableWidgetItem,
};
use std::rc::Rc;
use std::cell::RefCell;

//Struct for Main window
struct MainWindow {
    widget: QBox<QWidget>,
    button: QBox<QPushButton>,
}

//From form-struct to base-struct ??? 
impl StaticUpcast<QObject> for MainWindow {
    unsafe fn static_upcast(ptr: Ptr<Self>) -> Ptr<QObject> {
        ptr.widget.as_ptr().static_upcast()
    }
}

//Implementing functions for MainWindow
impl MainWindow {
    //Defining all the graphical elements in MainWindow
    //Returns the MainWindow in a Reference Counted Smart Pointer so it can have multiple owners
    //and doesn't get destroyed until it has no owners anymore
    fn new() -> Rc<MainWindow> {
        unsafe {
            //Widget
            let widget = QWidget::new_0a();
            let layout = QVBoxLayout::new_1a(&widget);

            //Label
            let label = QLabel::new();
            label.set_text(&qs("Label A!"));
            layout.add_widget(&label);

            //Button
            let button = QPushButton::from_q_string(&qs("Click me."));
            layout.add_widget(&button);

            widget.show();

            let this = Rc::new(Self {
                widget,
                button,
            });
            this.init();
            this
        }
    }

    //Binding functions/slots to elements etc
    unsafe fn init(self: &Rc<Self>) {
        self.button
            .clicked()
            .connect(&self.slot_build_option_a());
    }

    //Slots/Functions for buttons
    #[slot(SlotNoArgs)]
    unsafe fn build_option_a(self: &Self) {
        
        //DELETING all buttons, labels,...
        while self.widget.layout().count() > 0 {
            self.widget.layout().remove_item(
                self.widget.layout().item_at(0)
            );
                

            println!("{}", "Deleted something...");
        }
        //ATTEMPTS to delete the layout:
        //self.widget.as_mut_raw_ref().unwrap().layout().delete_later();
        //self.widget.layout().delete_later();
        //std::mem::drop(self.widget.as_mut_raw_ref().unwrap().layout());
        //std::mem::drop(self.widget.layout());
        //self.widget.layout().delete();
        //self.widget.as_mut_raw_ref().unwrap().layout().delete();
        //self.widget.layout().as_ref().unwrap().delete();
        
        //self.widget.[...].layout().as_ref().unwrap().delete()
        //self.widget.layout().as_ref().unwrap().delete()
        self.widget.as_mut_raw_ref().unwrap().layout().as_ref().unwrap().delete();
    

        //Building new layout etc
        let layout = QVBoxLayout::new_1a(&self.widget);

        //Label
        let label = QLabel::new();
        label.set_text(&qs("Label B!"));
        layout.add_widget(&label);
        
        //self.widget.as_mut_raw_ref().unwrap().set_layout(&layout);
        
    }
}

fn main() {
    QApplication::init(|_| unsafe {
        let _mw = MainWindow::new();
        QApplication::exec()
    })
}

[package]
name = "qt_rs_3"
version = "0.1.0"
authors = ["ONiel"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
cpp_core = "0.6.0"
qt_core = "0.5.0"
qt_gui = "0.5.0"
qt_qml = "0.5.0"
qt_widgets = "0.5.0"

Video to show what's wrong:
ezgif-3-935b59f31845

When the button is clicked Label A and the Click-me button should disappear, so only Label B is visible. Now the initial label and button are still visible...

EDIT:
Solved. Working code for people with the same question reading this thread via Google:

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