Hy Qlikers,
I'd like to share with you this tip that is quite usefull for me.
Maybe a smarter or more simple way exists to do that , but this way works really fine.
1 declare a new variable like below :

2 add filter selection with expression (=$Field) :

3 add a new dimension in your table ( i add a condition to hide the custom dimension if not selected)

Enjoy:).