Weird problem with MainWindow

Maybe today I must have something in my head very odd, because I cannot see why this simple program does not work.
The problem is that I cannot change at all the MainWindow's title, neither add some Menu,toolbar....
For example, in the code below, the word "OmniVision" doesnot appear in the MainWindow top bar, it just writes "MainWindow".

Code:

---

MainWindow::MainWindow( )
 
{
  this->setWindowTitle(tr("OminiVision "));
 
 
 
 
}

---

Code:

---

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
 
 
 
 
class MainWindow : public QMainWindow {
    Q_OBJECT
public:
    MainWindow( );

---

and the main.cpp is

Code:

---

#include <QtGui/QApplication>
#include "mainwindow.h"
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
     a.setApplicationName("OmniVision Japita SE");
    w.show();
    return a.exec();
}

---

Simpler than this...
I noted that if I put in the .pro "CONFIG = release", the problem is ther.
BUT: if I put "CONFIG = debug_and_release" everything is working (title, button, menu,and so on).
Why I have to use also debug?

I have no idea... but I'd try to isolate the problem by deleting the "tr" from this->setWindowTitle(tr("OminiVision "));.
After that you'd know whether there is something really serious going on or just a misbehaviour of the translation system.

(And of course, the age-old advice: if something mibehaves, reboot, clean and rebuild or in other words: delete everything that your build system (whatever it is) has generated and try again.)

You are right! I never had a suspect about tr() not working inside setWindowTitle.
Is it a bug or a rule?
G