C1PropertyGrid provides a reset button that allows users to reset a changed property to its default value (specified using the DefaultValue attribute). The reset button is small rectangle next to the property editor:

By default, the Reset button is not shown, but you can make the Reset button visible by setting the C1PropertyGrid.ShowResetButton property to True. It’s important to note that the SelectedObject should implement the INotifyPropertyChanged interface so it can reflect the updated value; this is because bound properties must notify value changes to the editor so it can refresh values.