Filter and Slicer doesn't do the same result

I use a table where my result are regrouped in categories and metacategories.  (phone call in queue and categories, and regroupement)

ex 

call        | queue | Categorie | MetaCategorie

10101   |  A        |     Level 1 |      Technical

10102   |  B        |     Level 1 |      Technical

10103   |  C        |     Level 2 |      Technical

10104   |  D        |     Level 2 |      Technical

10105   |  E        |     Level 3 |      Software

10106   |  F        |     Level 3 |      Software

10107   |  G        |    Level 4 |      Software

I want to see only Level 1

If I use a slicer (visualization tool) in my page to show only some categories (Level 1), the metacategories that have other categories (Level 1 & Level 2) on it are show with all the data of the categories in the metacategorie

But, If I use the filter in the right pane, tada, only the selected categories (Level 1) are show, like it should be.

Why, and how to chance this behavior ? Because, I don't want my end user to use the Filter pan, only the slicer in the report. So supervisor from the Level1, can't see the Level 2 data...