selectionColor property Null safety
The color to use when painting the selection.
If this property is null, this widget gets the selection color from the DefaultSelectionStyle.
For CupertinoTextFields, the value is set to the ambient CupertinoThemeData.primaryColor with 20% opacity. For TextFields, the value is set to the ambient TextSelectionThemeData.selectionColor.
final Color? selectionColor;