Expand clustered Key Figures in filter panel (based on BW queries)

Dear colleagues,

in my BW query, I have created several key figures and have clustered them below Error Categorization 1 and 2.

In my Design Studio application I use a filter panel to select the key figures. The goal is to show the first level (error cateogization 1 and 2) at a first view with the option to expand these so that the detailed categories can be shown and selected.

Currently only the subcategories are shown in the filter panel in Design Studio.

Could you help here?

Thanks,

Katharina