Hello all!

This code is a part of my MainWindow class constructor
Qt Code: 
  1. MainWindow::MainWindow()
  2. {
  3.    ....
  4.    dock = new QDockWidget(tr("Paragraphs"), this);
  5.    QLineEdit* l = new QLineEdit(0);
  6.    dock->setWidget(l);
  7.    dock->setFeatures(QDockWidget::NoDockWidgetFeatures);
  8.    dock->setFloating(false);
  9.    addDockWidget(Qt::BottomDockWidgetArea, dock);
  10.    ....
  11. }
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It works fine!

Why this code is incorrect (dock widget is invisible):
Qt Code: 
  1. MainWindow::MainWindow()
  2. {
  3.    ....
  4.    dock = new QDockWidget(tr("Paragraphs"), this);
  5.    QLineEdit* l = new QLineEdit(0);
  6.    dock->setWidget(l);
  7.    dock->setFeatures(QDockWidget::NoDockWidgetFeatures);
  8.    dock->setFloating(false);
  9.    addDockWidget(Qt::BottomDockWidgetArea, dock);
  10.    removeDockWidget(dock);                           /// Remove 
  11.    addDockWidget(Qt::BottomDockWidgetArea, dock);    /// And add again
  12.    ....
  13. }
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