In order to define a contextual action for pointset layers, you need to put your Python script in your Python directory under a directory called Contextual_XSection_PointSet_Layer.
Go to Tools->Options->Environment->Python Scripts (or Tools->Options->Python->Scripts in INTViewer 5.2) and click "Refresh from Disk". Your script should be listed automatically.
You will now be able to execute this script from the contextual menu of the pointset layer:
This script will decimate the pointset, update its colormap to match the new limits, apply a symbol map and finally add a colorbar and symbol bar to
the window.
This script is attached to the bottom of this article.
The result after the script executes should look something like the following: