Navigation between 3 (or more) window ?

Hello,

I have a problem to navigate between 3 or more windows.

I have a mainwindow, a window_1 and a window_2.
On each window i have a button to open a new window and hide the actual one, and a button to close the window and access to the previous one.

My problem is when I am on the window_2 and i want to close it, when the program close the actual window and try to access to the previous one, it show me the 2 others ones and crash.

Here is my code to open and close :

Code:

---

void window_1::_pushButton_open_clicked()
{
    this->hide();
    window_2 *w = new window_2();
    w->exec();
    this->show();
}
 
void window_2::_pushButton_close_clicked()
{
    this->close();
}

---

I think my problem come to "this->close" and "this->show()" which is dont take mu previous window.

Thanks for your help, i hope that clear enough.