I investigated this topic and found a workaround. The idea is to set the DIV to transperent before render, and make this visiable after render callback:
<div id='chart_container'> </div>
...
FusionCharts.ready(
function () { document.getElementById('chart_container').style.opacity = 0.0; chart = new FusionCharts(...); chart.render(); }
); function FC_Rendered(DOMId) { document.getElementById('chart_container').style.opacity = 1.0; }