close button not there in Mac but its in window

[netmat]

MyControlPanel::MyControlPanel(QWidget *parent) :
QFrame(parent, Qt::Window)
{
 
     setWindowTitle("Web SDK Simulator");
 
    setupUi(this);   	
	MySettings::instance()->setParent(this,Qt::Window | Qt::WindowSystemMenuHint);
}

MyControlPanel::MyControlPanel(QWidget *parent) :
QFrame(parent, Qt::Window)
{
	
     setWindowTitle("Web SDK Simulator");
    
    setupUi(this);   	
	MySettings::instance()->setParent(this,Qt::Window | Qt::WindowSystemMenuHint);
}

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I have code like this where I am creating a widget Setting which is child of Control Panel (type QFrame).
The setting widget not showing any button on Mac while its display close button on title bar rightly.

I have tried many options of window flags but to no avail.
Pls menation if I am missing something or any work around to achoieve this.

Ton of thanks,
-netmat