Unable to select multiple values in filter

[a-5]

Hi,

I have tried to google for a solution for this problem, but didn't find any. Hence, posting a question here: 

How can you specify if the user can select 1 or multiple values in Filter dimension? Currently, I'm able to select only one value in the Country dimension, but it should be possible to select multiple countries. If I press ctrl and manage to quickly select e.g. 2 countries, I get the attached error message (Invalid parameters). 

Behind the Country dimension I have this formula: =aggr(Only({<[Account channel]={'Direct'}>}[Country]),[Country]), because I wish to include only countries with Direct account channel in the dimension list. 

Can you please assist?

Thank you for your assistance! 

[Aditya_Chitale]

Tried  your expression using sample data. Didn't return any error for me. Can you share sample qvf ?

Regards,

Aditya

[a-5 · Accepted solution]

Hi Aditya, 

Thank you for your comment! I actually managed to solve this by creating a country list in Data load editor.