I went through many different posts. Qlik should hide the legend using Null() in the expression (both in the measure and in the label).
I have also tried to use alt(expression, null()) : still the same issue, the legend keeps coming back with the coloured square and - next to it.
Is it a qlik sense bug ?
Is there any extension that could fix this issue ?
I'm advancing with my issue
I had a similar behaviour with a pivot table located in the same report.
When using if ($(vAffichageTarget)>0,Sum([2018 Target]), Null()), the pivot table was showing - in the target 2018 column instead of hiding the column.
There is an option below the the pivot table expressions "Display column if":
This option did the job !
Is there an option for doing the same with charts ?...or a way to do the same ?