Hi,
WPF ships with a number of styles such as Luna, Aero, Classic, etc. These themes are applied based on your system settings. The screenshot from the previous post looks like the WPF Classic theme, but I'm guessing you're looking for a more appealing theme.
If you’re using a Classic system theme on your OS but would like your WPF application to use the Aero theme for example, you can add a merged dictionary to your app and force the Aero theme as shown below. Please note that you may need to change the binary version and public key accordingly.
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary
Source="/PresentationFramework.Aero;V4.0.0.0;31bf3856ad364e35;component\themes/aero.normalcolor.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
Hope that helps,
Saied K.