QLineEdit insight the QStatusBar problem

Hello. I have subclassed QMainWindow and in the Status bar I put a LineEdit.

Code:

---

QLineEdit *lineEdit = new QLineEdit;
  statusBar()->addWidget(lineEdit);

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The problem I have is that when I start the app the Status bar appears little bigger than it's normal size and after a second it becomes to the normal size. So I checked the sizeHint() of these two widgets:

Code:

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QLineEdit *lineEdit = new QLineEdit;
 qDebug() << statusBar()->minimumSizeHint(); // Status bar before adding the LineEdit's  Height(22)
 
 qDebug() << lineEdit->minimumSizeHint(); // LineEdit's Height (27)
 statusBar()->addWidget(lineEdit);
 
 qDebug() << statusBar()->minimumSizeHint(); // Status bar after adding the LineEdit (32)

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I saw that the LineEdit's height is bigger and the Status bar try to adjust the size. So I tried to set
lineEdit->setFixedHeight(19) and
statusBar->setFixedHeight(32) but it is still the same;

I tried with the setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Preffered) as well but nothing changed.

I use Ubuntu 12.04 and the program was run with diffrent styles (Plastique, CleenLooks) but the result is the same.
It's happening only when I have QLineEdit insight.

One more thing:
It happens mainly when I quit the app maximized or i switch from minimize to maximize. These are my Settings:

Code:

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void MainWindow::readSettings()
{
 
    QSettings settings("MySettings", "app");
    move(settings.value("position", QPoint(200, 200)).toPoint());
 
    QByteArray windowGeometry = settings.value("geometry").toByteArray();
    restoreGeometry(windowGeometry);
 
    QByteArray windowState = settings.value("state").toByteArray();
    restoreState(windowState);
 
}
 
//==========================================================================================
 
void MainWindow::writeSettings()
{
 
 
    QSettings settings("MySettings", "app");
    settings.setValue("position", pos());
    settings.setValue("geometry", saveGeometry());
    settings.setValue("state", saveState());
}

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Can someone help me?