Incorrect location of RibbonQuickAccessToolBar of RibbonControl when RibbonWindow is in Maximized state

I am trying to create RibbonQuickAccessToolBar in the top of left corner of the "RibbonWindow". To implement it I use a library ofSystem.Windows.Controls.Ribbon.
It works very well till I set:

WindowState="Maximized"

Let me show what I've done to show RibbonWindow:

1. I inherited from RibonWiddow

public partial class MainWindow : RibbonWindow
{
   public MainWindow()
   {
      InitializeComponent();
   }
}

2. My XAML is:

<RibbonWindow x:Class="QuickAccessToolBarRibbonControl.MainWindow"
        ...The code omitted for the brevity...
        Title="Pls see my position" Height="350" Width="525" Margin="2" WindowStartupLocation="CenterScreen" WindowState="Maximized"><Grid><Ribbon x:Name="RibbonWin" ItemsSource="{Binding ribbonTabData}" ><Ribbon.QuickAccessToolBar><RibbonQuickAccessToolBar   ><Button Content="Hello World" Click="Button_Click" Margin="2"/><Button Content="Hello World" Margin="2"/><Button Content="Hello World" Margin="2"/></RibbonQuickAccessToolBar></Ribbon.QuickAccessToolBar></Ribbon></Grid></RibbonWindow>

Image when Window is not Maximized:

Image When WindowState="Maximized":

What I want is to locate QuickAccessToolBar like in Paint:

My question is how can I align buttons and Title to look like in MS Paint?

Any help would be greatly appreciated!