Groupby bug in grid

Suite and Optimus Suite 5
#1

I use #stat_total in groupby,and I meet this problem:

In case of one group,I got the right stat_total like ‘151.16’;
In other case,I got the bug,the sta_total likes ‘120.8500000001’ or ‘920.99999999999’.

who can tell me why?I need help.

here is part of my code:

function grid_gorupby(index){
    myGrid.groupBy(index,["","#title","#cspan","#cspan","#stat_total","#cspan","#cspan","","","","",""]);
}

I learn this code soulation from the sample on dhtmlx.comhttp://dhtmlx.com/docs/products/dhtmlxGrid/samples/07_extended_modes/01_pro_group.html.

#2

Could you please, provide with a complete demo or a demo link, where the problem can be reconstructed locally.