SelectionMenu constructor
      const
      SelectionMenu({ 
    
    
- required WidgetBuilder selectorBuilder,
- required DropDownButtonBuilder? buttonBuilder,
- SelectionMenuController? controller,
- LayoutSelectPop? layoutSelectPop,
- DropDownPopCreated? onCreated,
- DropDownPopShow? onShow,
- DropDownPopDismiss? onDismiss,
- bool enableOnHover = false,
- bool enableClick = true,
- bool matchParentWidth = true,
- double popWidth = 0,
- double hMargin = 0,
- double vMargin = 0,
- double popHeight = 200,
- BorderRadiusGeometry? materialBorderRadius,
- Color? color = Colors.transparent,
- ShapeBorder? shape,
- double elevation = 0.0,
- Color? shadowColor,
- String? barrierLabel,
- Color? barrierColor,
- bool barrierDismissible = true,
- Duration transitionDuration = const Duration(milliseconds: 200),
- AlignType alignType = AlignType.left,
- GestureTapCallback? onDoubleTap,
- GestureLongPressCallback? onLongPress,
- GestureTapDownCallback? onTapDown,
- GestureTapUpCallback? onTapUp,
- GestureTapCancelCallback? onTapCancel,
- ValueChanged<bool> ? onHighlightChanged,
- ValueChanged<bool> ? onHover,
- MouseCursor? mouseCursor,
- Color? focusColor,
- Color? hoverColor,
- Color? highlightColor,
- WidgetStateProperty<Color?> ? overlayColor,
- Color? splashColor,
- InteractiveInkFeatureFactory? splashFactory,
- double? radius,
- BorderRadius? borderRadius,
- ShapeBorder? customBorder,
- bool enableFeedback = true,
- bool excludeFromSemantics = false,
- FocusNode? focusNode,
- bool canRequestFocus = true,
- ValueChanged<bool> ? onFocusChange,
- bool autofocus = false,
- Key? key,
Implementation
const SelectionMenu(
    {required this.selectorBuilder,
    required this.buttonBuilder,
    this.controller,
    this.layoutSelectPop,
    this.onCreated,
    this.onShow,
    this.onDismiss,
    this.enableOnHover = false,
    this.enableClick = true,
    this.matchParentWidth = true,
    this.popWidth = 0,
    this.hMargin = 0,
    this.vMargin = 0,
    this.popHeight = 200,
    this.materialBorderRadius,
    this.color = Colors.transparent,
    this.shape,
    this.elevation = 0.0,
    this.shadowColor,
    this.barrierLabel,
    this.barrierColor,
    this.barrierDismissible = true,
    this.transitionDuration = const Duration(milliseconds: 200),
    this.alignType = AlignType.left,
    this.onDoubleTap,
    this.onLongPress,
    this.onTapDown,
    this.onTapUp,
    this.onTapCancel,
    this.onHighlightChanged,
    this.onHover,
    this.mouseCursor,
    this.focusColor,
    this.hoverColor,
    this.highlightColor,
    this.overlayColor,
    this.splashColor,
    this.splashFactory,
    this.radius,
    this.borderRadius,
    this.customBorder,
    this.enableFeedback = true,
    this.excludeFromSemantics = false,
    this.focusNode,
    this.canRequestFocus = true,
    this.onFocusChange,
    this.autofocus = false,
    Key? key})
    : super(key: key);