To edit a 2D-Cam, Gear-Pair, Profile, Extrusion.
There are certain elements that are coincident with each other in the graphic-area.
For example: A Polyline element may be above a 2D-Cam, and a Profile/ Extrusion element may be above the Polyline.
When you want to edit one of these elements - the - you may find you open a dialog-box that you do not want to open.
To edit the element that you want to edit 2D-Cam, Polyline, Profile, or Extrusion
There are two basic procedures:
PROCEDURE 1 - Selection-Window [preferred]
All of the coincident elements will show in the Selection-Window
PROCEDURE 2 - Assembly-Tree