Aggregation preview feature not working

Hello there,

I just try the new aggregation feature that sounds so powerfull but it doesn't work if I add dimensions from linked tables (in import mode).

If I select dimensions or measures that are in the manage aggregations module, it works : it's very fast to show the data (in a table or a chart, ...). But if I select a linked (through a relation) dimensions (in another table), it takes 30 seconds to show the data, so it goes through the directquery (and not through the aggregated table).

Did someone have an idea what can be wrong ?

Thanks a lot !

Fabrice