void HitTestCoreWithPrevChainHint(HitChain hitPointChain, HitChain previousChain, int x, int y)
{
//---------------------------------
//test on previous chain first , find common element
hitPointChain.ClearAll();
hitPointChain.SetStartTestPoint(x, y);
//if (this.dbugId > 0 && isDragging && previousChain.Count > 1)
//{
//}
//RenderElement commonElement = HitTestOnPreviousChain(hitPointChain, previousChain, x, y);
//temp fix
//TODO: fix bug on HitTestOnPreviousChain()
RenderElement commonElement = this.topRenderElement;
////use root
//if (isDragging)
//{
// if (commonElement != this.topRenderElement)
// {
// }
//}
//if (lastCommonElement != null && commonElement != null &&
// lastCommonElement != commonElement && isDragging)
//{
// Console.WriteLine(commonElement.dbug_GetBoundInfo());
//}
//if (commonElement == null)
//{
// commonElement = this.topRenderElement;
//}
//if (commonElement != this.topRenderElement)
//{
//}
//lastCommonElement = commonElement;
commonElement.HitTestCore(hitPointChain);
//this.topRenderElement.HitTestCore(hitPointChain);
}