html - Why doesn't my iron-list items reset when I have a div (still inside the list) on top of main elements? -

i have iron-list bunch of objects i'd them reposition upon occurring event changes input data iron-list. need each object reference top of list , have not found solution yet. way can them act absolute objects put div before main item see below. when change data number of items stay same , (as many new elements in array) reposition. if there more items left previous data, stay though binding heights read data.

      <iron-list id="myid" items="[[myinput]]" as="myitem" selection-enabled multi-selection>         <template>                         <!-- have have main items position referenced top of iron-list -->         <div id="referencediv" style="left:0px; float:left; width: 100%; min-height:1px; background-color:blue; top: 0px; display: none;"></div>          <div id="mainitemid" style$="background-color:#fff; height:[[myitem.height]]px; top:[[myitem.top]]px; border-radius: 3px; border-color:#333; border-width:1px; border-style: solid;;"></div>          <div id="bottomguidid" style="left:0px; float:left; width: 100%; min-height:1px; background-color:lightblue; top: 1920px;"></div>          </template>       </iron-list>