Draw element from points ,after grouping element ,I can't drag the groupelement,why

[luyun]

Hi

I draw element from points ,after grouping element ,I get Groupelement,then use GraphicsContainer.add(groupelement as Ielement,0),all the element display on screem.but I can't drag the groupelement,why?
if I add the rectangle bar on the axToolbar ,draw elements ,and group then I can Draw the groupelement.
Can you help me ?
Thank you

[luyun]

I find the reason,after grouping,the element.geometry isempty=true.but why?how can i do?