Problem: 

If you try to edit a Mold Tooling Pattern occurrence, you cannot select the coordinate system representing the occurrences in the Edit Occurrences step.

Description:

In Solid Edge ST, if you hide all coordinate systems in the top level assembly without any existing coordinate system in the top level assembly, and later create a coordinate system in it, like we do during the pattern occurrence edition, the individual coordinate systems have the visibility checked but are not visible as the collection is unchecked.
The visible coordinate systems are only OpenGL previews during the edition and are not selectable. You can easily distinguish the OpenGL preview from the locatable Coordinate System by the missing x,y,z characters at the end of the coordinate system axis.
You will only be able to select the coordinate system and edit the occurrence, if the characters at the axes are present.

Solution:

During the edition, you should open the Assembly PathFinder Tab and check the box left to the Coordinate Systems collection of the top level assembly. This will display all created coordinate systems and allow you to select them.

Remark:

The problem remains in the current version as there is no API function to enable the visibility of the Coordinate Systems collection. A problem report was filed to add the visibility property to the collection, so that we can make the collection visible before starting the pattern occurrence edition. Unfortunately, this API functionality does not yet exist.