title: The argument type 'MaterialColor' can't be assigned to the parameter type 'MaterialStateProperty<Color>
body: <p>I have a question related with the new ElevatedButtonThemeData widget, basically I want to set the background color for all ElevatedButtons in my app, I'm struggling trying to set it up in the ThemeData definition by doing:</p>
  <pre><code>      theme: ThemeData(
          ...
          elevatedButtonTheme: ElevatedButtonThemeData(
              style: ButtonStyle(backgroundColor: Colors.red)), // Here Im having the error
          ...
          ),
        ),
  </code></pre>
  <p>Error:</p>
  <pre><code>The argument type 'MaterialColor' can't be assigned to the parameter type 'MaterialStateProperty&lt;Color?&gt;?'.dartargument_type_not_assignable)
  </code></pre>