public DoubleProperty startProperty() {
        if (null == start) {
            start = new DoublePropertyBase(_start) {
                @Override protected void invalidated() { fireSectionEvent(UPDATE_EVENT); }
                @Override public Object getBean() { return Section.this; }
                @Override public String getName() { return "start"; }
            };
        }
        return start;
    }
Defines the value where the section begins.
@param START
src/main/java/eu/hansolo/tilesfx/Section.java