Adding SubWindow to a MDI Area will not work inside a slot function

billconan

I am wondering if this is a known bug, or I simply missed something.

What I want to do is simple: Adding a sub window to an MDI area.

@mdiArea->addSubWindow(new QWidget());@

this line of code works fine if it inside the constructor of my window class.

But I want to add the subwindow by clicking a button.

if the "adding sub window" code is inside the button's slot function, it will not work anymore. Nothing will appear within the mdi area.

I am developing under Mac OS Lion with Qt4.8

here is my code:

@MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

addSubWindow= ui->mainToolBar->addAction("Add SubWindow");

connect(addSubWindow,SIGNAL(triggered()),this,SLOT(onAddSubWindow()));

//This line can add a sub window to the mdi area
//ui->mdiArea->addSubWindow(new QWidget());

}

void MainWindow::onAddSubWindow()
{
//but if add a sub window from a slot function, it will not work. nothing will appear within the mdi area.
ui->mdiArea->addSubWindow(new QWidget());
}

MainWindow::~MainWindow()
{
delete ui;
}
@

here is my qt project that repros this issue :http://dl.dropbox.com/u/3315090/mdibug.zip

billconan

This is not a bug, I figured out why after looking at the MDI example.

I need to call SubWindow->show() after I add it to the mdi area.