QMessageBox that blocks only the current QMdiSubWindow?

[dv8]

Thanks Santosh, for the insights!
I'm currently trying to implement your idea and it is working nicely, but there is one issue I can't get passed.
I have made the following simple class:

namespace Ui {
   class MyMessageBox;
}
 
class MyMessageBox : public QWidget
{
   Q_OBJECT
 
public:
   explicit MyMessageBox(QWidget *parent = 0, QString Title="Message box", QString Content="");
   ~MyMessageBox();
 
private:
   Ui::MyMessageBox *ui;
};

namespace Ui {
   class MyMessageBox;
}

class MyMessageBox : public QWidget
{
   Q_OBJECT
   
public:
   explicit MyMessageBox(QWidget *parent = 0, QString Title="Message box", QString Content="");
   ~MyMessageBox();
   
private:
   Ui::MyMessageBox *ui;
};

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which visually resembles the original message box. It contains an Icon, a label to display the message in and an OK button.

What I'm doing to visualize it is:

MyMessageBox *msg=new MyMessageBox(*MyCustomTabWidget,Title,Message);
connect(msg,SIGNAL(destroyed()),this,SLOT(Continue()));
msg->setAttribute(Qt::WA_DeleteOnClose);
msg->setWindowFlags(Qt::SubWindow); //I've found that Qt::SubWindow flag is giving me the desired behavior
msg->show();
msg->raise();

MyMessageBox *msg=new MyMessageBox(*MyCustomTabWidget,Title,Message);
connect(msg,SIGNAL(destroyed()),this,SLOT(Continue()));
msg->setAttribute(Qt::WA_DeleteOnClose);
msg->setWindowFlags(Qt::SubWindow); //I've found that Qt::SubWindow flag is giving me the desired behavior
msg->show();
msg->raise();

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This message box is displayed over a QWebView which takes almost all the MyCustomTabWidget space. However, when it is displaying only the Icon, the Message text and the OK button are visible over the QWebView widget. The body and the title bar are not visible. I've made countless tests with different window flags, but nothing seams to help. Any suggestions, why this is happening and how I can fix it?