Collector.Area not working

Hi everyone, I am very keen on Dynamo and trying to practice some graphs. Recently, I found that Collector.Area is very helpful but I can not use it. I did try several ways but still not working.
Is there any thing that I am missing? Many thanks.

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I am having the same issue. Anyone able to resolve this? PhamQuangDung where you able to fix this?

See in other threads maybe:
http://dynamobim.org/forums/topic/collect-areas/