title: Material Design In XAML override style not working
body: <p>I'm having difficulties overriding a very simple TextBox style using the MaterialDesignInXamlToolkit.</p>
  
  <p>As far as I can see I've followed the <a href="https://github.com/ButchersBoy/MaterialDesignInXamlToolkit/wiki/Overriding-Default-Styles" rel="nofollow noreferrer">override instructions</a> to the letter:</p>
  
  <p>App.xaml</p>
  
  <pre><code>&lt;Application x:Class="WpfApp1.App"
               xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
               xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
               StartupUri="MainWindow.xaml"&gt;
      &lt;Application.Resources&gt;
          &lt;ResourceDictionary&gt;
              &lt;ResourceDictionary.MergedDictionaries&gt;
                  &lt;ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Light.xaml" /&gt;
                  &lt;ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Defaults.xaml" /&gt;
                  &lt;ResourceDictionary Source="Themes/MaterialDesignTheme.Overrides.xaml" /&gt;
              &lt;/ResourceDictionary.MergedDictionaries&gt;
          &lt;/ResourceDictionary&gt;
      &lt;/Application.Resources&gt;
  &lt;/Application&gt;
  </code></pre>
  
  <p>MainWindow.xaml</p>
  
  <pre><code>&lt;Window x:Class="WpfApp1.MainWindow"
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          xmlns:materialDesign="clr-namespace:MaterialDesignThemes.Wpf;assembly=MaterialDesignThemes.Wpf"
          Title="MainWindow" Height="400" Width="300"&gt;
      &lt;Grid&gt;
          &lt;TextBox VerticalAlignment="Center"
                   x:Name="NameTextBox"
                   materialDesign:HintAssist.Hint="Name"&gt;
          &lt;/TextBox&gt;
      &lt;/Grid&gt;
  &lt;/Window&gt;
  </code></pre>
  
  <p>MaterialDesignTheme.Overrides.xaml</p>
  
  <pre><code>&lt;ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                      xmlns:materialDesign="clr-namespace:MaterialDesignThemes.Wpf;assembly=MaterialDesignThemes.Wpf"&gt;
  
      &lt;Style x:Key="MaterialDesignTextBox" 
             BasedOn="{StaticResource MaterialDesignTextBox}"
             TargetType="{x:Type TextBox}"&gt;
          &lt;Setter Property="FontSize" Value="200" /&gt;
      &lt;/Style&gt;
  
  &lt;/ResourceDictionary&gt;
  </code></pre>
  
  <p>However, unless I remove the <code>x:Key</code> from the style in the overrides file, the font in the text box stays at a very boring 12, rather than the super exciting <strong>200</strong> I'm after. </p>
  
  <p>I've created an example project on <a href="https://github.com/markbarks/md_xaml_override" rel="nofollow noreferrer">Github here</a>. If anyone could take a look I'd be very grateful.</p>