in attached sample file I would create a new list box element containing those combinations of AGENTE and CLIENTE pairs that don't have Periods value in its PERIODO_0 field.
For instance, about first pair "1, 100076" I would like to see as a final result:
Ok, this helps me to understand that if I temporarily disable your expression and if I add another one like:
If(1=0,1,0)
then all rows always are hidden due to 0 value always returned. Before your explanation I was convinced that with this kind of expression all rows should continue to appear with always a value of 0 aside. In fact, if the expression modifies to the opposite:
If(1=0,0,1)
or:
If(1=1,1,0)
now all rows return visible because in this case 1 value always returned (i.e. a value different from '0'). Is this correct?
