Button IsMouseOver

   
       
<Window x:Class="PropertyTrigger.Window1"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="PropertyTrigger" 
  Height="300" 
  Width="300"
  >
  <Window.Resources>

    <Style TargetType="{x:Type Button}">
      <Style.Triggers>
        <Trigger Property="IsMouseOver" Value="True">
          <Setter Property="Background" Value="Orange" />
        </Trigger>
      </Style.Triggers>
    </Style>

  </Window.Resources>

  <Grid>
    
    <Button 
      VerticalAlignment="Top"
      HorizontalAlignment="Stretch"
      Height="46"
      Name="button1"
      >
      Button
    </Button>
    
  </Grid>
</Window>