added an option to force the redraw of a list, even if the cached lists are the
same (which is the case when we just added another annotation)
{{! template for the slice widget }}
<div class='Ldt-sliceWidget'>
{{! the whole bar }}
<div class='Ldt-sliceBackground'></div>
<div class='Ldt-sliceLeftHandle'></div>
{{! the zone which represents our slice }}
<div class='Ldt-sliceZone'></div>
<div class='Ldt-sliceRightHandle'></div>
</div>