Color palette seems to not work as intended on Custom Visuals

Hi  there,

I have some problems on with our custom visuals depicting the default color for data points.

Steps to repreduce: 

1. The data is filtered to 3, 4, 5 and 6 (which are indented to be used as legend or data color).
2. The correct default colors are displayed.
3.  Add 2 
4.  Add 1
5.  Both get same default color as 3.

The same problem occurs on the Microsoft AsterPlot, see screenshot::  (The Attribute Slicer seems to reset the defaultcolors everytime). Is there any solution for this?

I am using the latest API 2.6.0.

Thanks in beforehand,