Restore minimized frameless window from Taskbar

Question

I'm creating one basic qml application with visibility:"FullScreen", and I have one button to minimize the application but after minimizing if i click on the exe in task bar its coming with framed application with min, max, close. I want it again in FullScreen mode.

applicationWindow
{
id:mainWindow
visible: true
visibility: "FullScreen"
Rectangle {
    id:rect
       width: 140
       height: 140
       color: "lightblue"
       anchors.centerIn: parent

   }
  Button{
     anchors.top: rect.bottom
    anchors.left: rect.left
    text: "Minimize"
    onClicked: {
        mainWindow.showMinimized()
    }
  }
}

After minimizing and trying to open from taskbar