I am using version 1.3.10 for IOS - latest available from store.
If I select a genre, say Boogie-Woogie, then select, I get a set of check boxes (see attachment) .
It count the the number of elements .
And the Play(Lire) button is live.
All cool.
To coherent, it should be possible to hit Select at the genre level, (previous level)
get the check boxes and select one or more genre to play.