Project Editions browser - do I need to add pre-reqs?

In the project editions browser - If I have a package the has pre-reqs A, B
do I need to add A,B to the project?

If so (I guess you need to, otherwise how does it know which version of the
pre-reqs to load for you?) - is there any way to get it to add / calculate
them for me, as its a painful process flipping between browsers to see what
they are and then click on the add button to add them.

Tim