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 slider widget - it's composed of two divs we one overlayed on top
of the other }}
<div class='Ldt-sliderBackground'></div>
<div class='Ldt-sliderForeground'></div>
<div class='Ldt-sliderPositionMarker'></div>