Why would a TextBlock with DropShadowEffect show a solid black background on one XP machine?

Question

We have a WPF application in which we have the following XAML:

<TextBlock x:Name="HeaderRightSubtitle"
        HorizontalAlignment="Left"
        VerticalAlignment="top"
        FontSize="10"
        Foreground="#FFFFFF">
        <TextBlock.Effect>
            <DropShadowEffect
       Color="#FFCACACA"
       ShadowDepth="1"
       Opacity="100"
       RenderingBias="Quality"/>
        </TextBlock.Effect>
</TextBlock>

It shows a nice shadow on all machines (XP, Vista) except for one XP machine on which is shows the white text on a solid, back, rectangle background also a bit offset. The XP has the same theme as the other machines.

Has anyone experienced this? What could be causing the DropShadowEffect to produce a solid black background on this one machine?

Answer 1

What video card is in the machine and are you using the latest version of drivers? Also, what version of DirectX is installed? If I had to guess, it's something with the card/drivers.

Answer 2

Check the version of .Net installed on the XP Machine. You might be missing SP2 for 3.0 or SP1 for 3.5.