Since I have received no reply, I try to better explain the issue and I have created a specific example for this.
The first list is 1,2,3... 10, the second list is the number of the first + a letter in alphabetical order.
So, if I want to select 5b, I first select 5, then I should see the second list filtered by 5, that is, only 5a, 5b, .... 5g.
Instead, the full list of values for the second list is report (see the attached image: if I select 1 I see 1a, 1b AND 2a, this means that filtering is not working).
The strange behaviour is that the same operation works in the BackOffice.....
Is anyone able to help me to solve this problem which is open for many weeks?
Thanks and regards