Keep Selected Filters State - FacetScope

I have in my search a “Keep Selected Filters” checkbox but if I uncheck the checkbox and submit a new search the checkbox state is still checked.

      <div class="filters sq-form-question-tickbox-list">
                        <ul>
                          <li>
                          <@s.FacetScope> keep selected filters</@s.FacetScope>
                          </li>
                        </ul>
                    </div>    

How does this keep its checked/unchecked state? In my case it’s always checked.

UPDATE: I realise now how that facetscope works so disregard my question

Thanks
NickyP