Flutter RawMaterialButton won't get transparent - flutter

Question

I'm using this simple CircularButtonWithIcon. The one problem is that it won't respect transparency when no color is setted.
class CircularButtonWithIcon extends StatefulWidget {
CircularButtonWithIcon({
Key key,
#required this.onPress,
this.padding,
this.border,
this.active = false,
this.marginRight,
this.marginLeft,
this.icon,
this.color,
this.activeColor,
this.text,
this.splashColor,
this.image,
this.hasState,
this.borderColor,
}) : super(key: key);
final double padding;
final double border;
final double marginRight;
final double marginLeft;
final Icon icon;
final Image image;
final Color color;
final Color activeColor;
final Color borderColor;
final Widget text;
final Color splashColor;
final Function onPress;
final bool active;
final bool hasState;
#override
_CircularButtonWithIconState createState() => _CircularButtonWithIconState();
}
class _CircularButtonWithIconState extends State<CircularButtonWithIcon> {
bool active;
#override
void initState() {
super.initState();
active = widget.active;
}
#override
Widget build(BuildContext context) {
return FittedBox(
child: Container(
margin: EdgeInsets.only(left: widget.marginLeft ?? 0, right: widget.marginRight ?? 0),
child: RawMaterialButton(
onPressed: () {
setState(() {
active = !active; // don't use widget.active
});
if (widget.onPress != null) widget.onPress();
},
fillColor: active
? widget.activeColor ?? widget.color ?? Colors.transparent
: widget.color ?? Colors.transparent,
splashColor: widget.splashColor ?? Colors.grey,
child: widget.text != null
? Container(
child: widget.text,
)
: widget.image ?? widget.icon,
//padding: EdgeInsets.all(15.0),
padding: widget.padding != null ? EdgeInsets.all(widget.padding) : EdgeInsets.all(15.0),
shape: CircleBorder(
side: BorderSide(
width: widget.border ?? 2.0,
style: BorderStyle.solid,
color: widget.borderColor ?? Colors.grey),
),
),
),
);
}
}
Take a look at:
fillColor: active
? widget.activeColor ?? widget.color ?? Colors.transparent
: widget.color ?? Colors.transparent,
When no color is seted, it should be transparent.
I did this:
CircularButtonWithIcon(
padding: 10,
border: 3,
onPress: () => {},
icon: Icon(Icons.remove,
color: Color.green,
size: 60))
and it's getting a color background instead of merging:
however it looks like it's just the background but darker. Is it possible that the button is adding a shadow on top of the background color? How can I remove it? I looked at https://api.flutter.dev/flutter/material/RawMaterialButton-class.html and couldn't find anything related to shadow effects on the button