WPF title bar controll get extended while maximize

I create a wpf window application i placed a control on the top left corner while maximizing my window that gets extended and goes back to normal in fraction of seconds like a white shade

<Windowx:Class="WpfApplication1.MainWindow"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"Title="MainWindow"Height="350"Width="525"WindowState="Maximized"WindowStartupLocation="CenterScreen"WindowStyle="None"AllowsTransparency="True"><GridBackground="#FF9D0000"><TextBoxText=""HorizontalAlignment="Left"VerticalAlignment="Top"Width="250"Height="40"Margin="10,0,0,0"></TextBox><ButtonHorizontalAlignment="Right"VerticalAlignment="Top"Click="Button_Click">Minimize</Button></Grid>

privatevoidButton_Click(object sender,RoutedEventArgs e){this.WindowState=WindowState.Minimized;}

and another thing while maximizing all other windows are minimized and maximized with some thing like animated. But my window is just disappears and appears

Edited 

If i set HorizontalAlignment="Center" its Normal

Kartikeyan