Steps to reproduce this issue:
Bind SelectedObject of a PropertyGrid to {Binding RelativeSource={x:Static RelativeSource.Self}}. The PropertyGrid inspects itself. Good, so far.
In Blend:
Right-click the PropertyGrid, select Edit template --> Edit copy... (hopefully it's right, I've a german Blend).
Save the style unmodified. From now, the PropertyGrid will not show any properties anymore.
Bind SelectedObject of a PropertyGrid to {Binding RelativeSource={x:Static RelativeSource.Self}}. The PropertyGrid inspects itself. Good, so far.
In Blend:
Right-click the PropertyGrid, select Edit template --> Edit copy... (hopefully it's right, I've a german Blend).
Save the style unmodified. From now, the PropertyGrid will not show any properties anymore.