hierarchy problem with charts - Open Hierarchy nodes visible

Hello Gurus,

My problem is that, I can't find a way to hide root element of the hierarchy in the charts.

Let's say we have a 3 level hierarchy,

Root

     a

          a1

          a2

          a3

     b

          b1

          b2

     c

          c1

          c2

.....

When I want to create a pie/bar chart containing the hierarchy elements, the parent of the elements also are added to chart. I tried to change it in the initial view, but it adds automatically the root even I choose only a1,a2,a3 in the filter selection.

I mean, if {a, b, c} is choosen in the filter of the query, in the chart we see {Root, a, b,c}.

if {a1, a2, a3}  is choosen in the filter of the query, in the chart I have {a, a1, a2, a3 }.

I hope, I clearly explained my problem.

In Web application designer there was a property called open_hierarchy_nodes_visible, it does the exactly thing that I need. (you can see the below picture)