Add to mdiArea using C++ code and QTDesigner

[Anonymous_Banned275]

SOLVED
...using KISS and let the mdiArea do the dirty work

   // TASK add mdiArea sub / child window - QMdiArea
     QMdiArea *qmdiarea = new QMdiArea();
     m_mdiarea->addSubWindow( qmdiarea);
     qmdiarea->setWindowTitle(" Common hcitool (QMdiArea )"); // TOK
     QWidget *qWidget = new QWidget(); // test 
     qmdiarea->addSubWindow( qWidget);
     qmdiarea->addSubWindow( qWidget);
     qmdiarea->addSubWindow( qWidget);

     qmdiarea->tileSubWindows();

Hello,
I am asking for actual C++ code and opinions / suggestions / help with the tasks.
( current code compiles/ links/runs.)
I need help with

1. adding QTabWidget INTO QWidget (mdiArea sunwindow) - NOT to mdiArea main parent !
2. adding existing (loop) QWidget BUILD using QrDesigner into specific tab . (Is that even possible??)

I am including current (work in progresses) actual, partially working , copy of my code.
I have highlighted areas I need help with and would appreciate if you could annotate / add your corrections / suggestions.

Your suggestion DOES NOT have to compile, I can manage that by myself.

Many thanks, appreciate actual C++ code where needed

  // TASK add mdiArea sub / child window - QWidget
    //  QWidget create
    QWidget *qWidget = new QWidget();
    m_mdiarea->addSubWindow( qWidget);
    qWidget->setWindowTitle(" Common hcitool (QWidget  )"); // TOK
    // create  QTabWidget
    QTabWidget *tabWidget;
    tabWidget = new QTabWidget(this); // sort of works
    // create layout and add it to tabWidget
    QHBoxLayout *layout = new QHBoxLayout;
    **layout->addWidget(tabWidget);**     // sort of works
    //**issue - shows in parent mdiArea** 
    //i**ssue - shows small size**
    //?? crashesb tabWidget->setLayout(layout);
    //tabWidget->show();
    //**TODO show full size in mdiArea sub wiundow** 

    //tabWidget->maximumSize();
    // add tabs in loop OK
    // for index ....
    tabWidget->addTab(qWidget, "TEST first tab ");
    ****
    

This is my "run"

Notice small "TEST.. " tab title showing attached in upper left corner. Wrong size and location!