In the instanceStarted() example in the README we demonstrated how an
application can bring it's primary instance window whenever a second copy
of the application is started.
On Windows the ability to bring the application windows to the foreground is restricted, see AllowSetForegroundWindow() for more details.
The background process (the primary instance) can bring its windows to the
foreground if it is allowed by the current foreground process (the secondary
instance). To bypass this SingleApplication must be initialized with the
allowSecondary parameter set to true .
If the widget is minimized to Windows task bar, QWidget::raise() or
QWidget::show() can not bring it to the front, you have to use Windows API
ShowWindow() .
You can find demo code in the examples directory.