title: The argument type 'Color?' can't be assigned to the parameter type 'Color'
body: <pre><code>class _CreateRoomButton extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     // ignore: deprecated_member_use
    return OutlineButton(
      onPressed: () =&gt; print('Create Room'),
       color: Colors.white,
    borderSide: BorderSide(width: 3.0, color: Colors.blueAccent[100]),
    textColor: Palette.facebookBlue,
    child: Row(
      children: [
        Icon(
          Icons.video_call,
          size: 35.0,
          color: Colors.white,
        )
      ],
    ),
    shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(30.0)),
  );
  }
  }
  </code></pre>
  <p>I have used an Outline Button in which I wanna set the border color to blueAccent[100]. On trying to do so the following error comes up :</p>
  <p>The argument type 'Color?' can't be assigned to the parameter type 'Color'.</p>
  <p>Also I wanna shift the outline button into the new Outlined Button but I am unable to style that acc to the app.</p>