Export Paraview 2d Transfer Function for use with vtk

Hello all!

Can someone help me to save my 2D transfer function?
In the image below you can see that the button is not available.

What I did so far:

  1. loading of vtk volume data
  2. representation as volume
  3. editing of color map
  4. checkmark set at Edit 2D Transfer function

My paraview version is the latest: 5.11.1

My plan was to use Paraviews user interface for the design of the transferfunction and then export it to a vtk suitable format (For the use of my own vtk-Skript)