public void setChecked( Boolean value ) {
		setState( (value == null) ? State.INDETERMINATE : (value ? State.SELECTED : State.UNSELECTED) );
	}
Sets the state as {@link Boolean}.
Passing {@code null} sets state to {@link State#INDETERMINATE}.
flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/components/FlatTriStateCheckBox.java