I have 2 List Boxes on different pages with a Button like this:

```
<ListBox x:Name="mainlist" >
      <Button x:Name="but1" />
</ListBox>

```

and second 

```
<ListBox x:Name="secondlist" >
    <Button x:Name="but2" Tag="but1" Click = "button_click" />
</ListBox>

```

On Application Initialization I set the Opacity of but 1 to 0 :

```
 public Main()
 {
       InitializeComponent();
       but1.Opacity = 0;
 }

```

and I want that when I press but2 to set Opacity to 100 for but1:

```
private void button_click(object sender, RoutedEventArgs e)
{
    var name = (sender as Button).Tag.ToString();
    object item = mainlist.FindName(name);
    if (item is Button)
    {
        (item as Button).Opacity = 100;
    }
}

```

But this does not update the but1 opacity. So the question is how to force update?