Extract selection combined with integrate variables filter results in 0

I have a slice which i use extract selection to get the desired output. When i use the integrate filter on it all variables will get the value 0 and i dont how to fix that. The interesting thing is, when i use a python calculator to get the area of the values i get that: Area = -1 , Cell Type = Vertex

When i use the integrate variables filter directly on the slice it works. As you can see when i use also a python calculator to get the Area. Area has values, and Cell Type = Triangle

I guess it has something to do with that area = -1 and the Cell Type. Any ideas if this beaviour is intendet and how to get the integrated values out of an extraction? Thank you very much.

regards David

When ExtractSelection1 is displayed in Spread Sheet View, does the Cell Type include 2D elements in addition to Vertex?

ExtractSelection only includes Vertex.
Slice only includes Triangle.

The slide is a multiblock dataset and works with an integrate filter
The extract selection is also a mutliblock dateset but the integrate filter doesnt work (all arrays = 0)

How to integrate values from a extraction then? Anyone knows?