Collection rules and containers 

All parametric objects created by the user are collected in containers. A Container icon is similar to the Rhino group icon. If a container is deleted, all contained objects are also deleted. The Rhino group command is not interpreted by RhinoParametrics, so a container will not be created when a Rhino group is created.
The "Param. Objects" root in the treeview is a container , and "contruction planes" objects are 2D containers  .

All objects are agregated in Container object or in the root project .

The active container is underlined in dark green in the treeview. By default, it is the root. New 3D containers can be created. Upon creation, the new container automatically becomes the active container. To make a different active container, right click to open the  contextual menu and select "Active Container" or make a double click on the container node.

Only Points XYZ are collected in the construction planes , the construction plane must be active. "construction planes" objects are represented in Rhino views by a square with thick edges.  See step 4 , which details the specifics of "Construction planes" objects.

It's possible to move a Container and all its sub objects in the treeview with a Drag&Drop. It's possible to copy a Container and all its sub objects by making a Drag&Drop with the "ALT" key pressed. Step 13 of this documentation is dedicated to this feature.