How to detecte theme in WPF's Xaml?
I have a custom control that needs a minor adjustment when running on XP or Vista with the Aero theme, is there a simple way to detect the theme (operating system detection isn't enough because the user can change the theme) and use this in a style trigger?

I need to apply a small margin change on Vista to get the look required:

            <Setter Property="Margin"
                    Value="0,-1,0,-1" />

The above setter is currently unconditional (e.g. not in a Trigger) but requires me having two versions.  

Ideally the solution should be Xaml only, but if necessary I could expose a property to associate to a datatrigger.
How to detecte theme in WPF's Xaml?
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I have a custom control that needs a minor adjustment when running on XP or Vista with the Aero theme, is there a simple way to detect the theme (operating system detection isn't enough because the user can change the theme) and use this in a style trigger?

I need to apply a small margin change on Vista to get the look required:

            <Setter Property="Margin"
                    Value="0,-1,0,-1" />

The above setter is currently unconditional (e.g. not in a Trigger) but requires me having two versions.  

Ideally the solution should be Xaml only, but if necessary I could expose a property to associate to a datatrigger.