When I try this, all the buttons turn blue, but the content isn't set.
<Window.Resources>
<Style TargetType="{x:Type Button}">
<Setter Property="Background" Value="Blue"/>
<Setter Property="Content" Value="Edit"/>
</Style>
</Window.Resources>
Any ideas?
EDIT : This example was indeed somewhat too oversimplified. My problem was in changing styles in runtime, where the color was changing allright, but not the content. The solution for me was not to initialize content in xaml, but in code.