Scroll to div problem in Firefox and IE

[Gee Jay Almestas]

Have problems with firefox 33.1 also IE but dont mind all i want is to have same in both fox and chrome, my scroll to div is not directing to my target div id when i click my navigation it's just going anywhere like 300px short to specified div target i have 4 div id targets starting from about, works, skills, & contact the first div id is working fine the next target id's are i guess 300px short. but its working absolutely fine using chrome

im using polymer core-scaffold as my navigation 

and i don't have any errors on my chrome console

but in my firefox console i do have "mutating the [[Prototype]] of an object will cause your code to run very slowly" in platform.js

here's my script

<script>

    var scaffold = document.getElementById('scaffold');
    var menu = document.getElementById('menu');

    menu.addEventListener('core-select', function(e) {
      if (e.detail.isSelected) {
        scrollToSection(e.detail.item.getAttribute('name'));
      }
    });

    function scrollToSection(id) {
      var section = document.getElementById(id);
      if (section) {
        scaffold.$.headerPanel.scroller.scrollTop = section.offsetTop;
      }
    }

  </script>

here's my navigation code

<core-scaffold id="scaffold" responsiveWidth="640px">
<core-header-panel navigation flex mode="seamed">
<core-toolbar>Navigation</core-toolbar>
<core-menu id="menu">
<core-item name="drawerPanel" icon="home" label="Home"><a href="#"></a></core-item>
<core-item name="about" icon="account-circle" label="Who"></core-item>
<core-item name="works" icon="work" label="Works"></core-item>
<core-item name="skills-cont" icon="gesture" label="Skills" name="skills"></core-item>
<core-item name="contacts-cont" icon="settings-phone" label="Contacts"></core-item>
<core-item name="cart" icon="shopping-cart" label="D Shop"><a href="#" target="_blank"></a></core-item>
<core-item name="v8" icon="link" label="v8"><a href="" target="_blank"></a></core-item>
<core-item name="v7" icon="link" label="v7"><a href="" target="_blank"></a></core-item>
<core-item name="v6" icon="link" label="v6"><a href="" target="_blank"></a></core-item>
</core-menu>


<div id="about">
<about-koh></about-koh>
</div>


<div id="works">
<works></works>
</div>

....

thank you so much in advance