WPF - White border in win 7

I have the following code for a button:

开发者_StackOverflow社区<Button Content="Logoff" FocusVisualStyle="{x:Null}" 
        Background="Transparent" BorderBrush="{x:Null}" BorderThickness="0"/>

In my current OS Win 7 i still get a white border. How can i remove this?

The white border appears because of the default chrome of the button.Chrome classes are theme specific.You can completely customize it according to your liking or else you can completely delete the chrome of the button control.Check the below posts for more

How to remove ButtonChrome border (when defining the template of a border)?

Get rid of button border in WPF?

How do you completely remove the button border in wpf?