system tray problem

[vvdounai]

hello, everyone!

I designed a program, I use F12 to invoke its minimize to try action. And the user can restore the window with tray icon menu.

I use a slot function as follows:

void mainwindow:: minimizetotraySlot()
{
if (isHidden())
{
   show();
   trayIcon->hide();
}
else
{
    hide();
    trayIcon->show();
}
}

void mainwindow:: minimizetotraySlot()
{
if (isHidden())
{
   show();
   trayIcon->hide();
}
else
{
    hide();
    trayIcon->show();
}
}

To copy to clipboard, switch view to plain text mode 

And I define a tray icon menu as

restore, quit, about.

however, when I select the about item in the tray icon menu, after the about dialog displayed, the application will quit. I don't know why? The about dialog is only a common MessageBox.