I found the answer to my own question. This was just a racecondition. You can't read the size of the ArrayCollection rightaway. The list takes a while to populate.

Hi,I am new to FDS and don't know why the fill() method returnsnothing, even though the assembler is returning a list of 3objects. I know the list is returning nothing because when Idisplay the length of the ArrayConnection, it's 0.I turned on debug logs and see the 3 items returned. Do youhave any ...