Parts (Not Loaded) when opening Shaper file

I am still very new so still learning. I have tried hard to search for a solution to this problem.

When I open my file in Shaper, only one part (the last modified) appears in the Part set. All the rest show “Part x (Not Loaded)” and I have to manually activate each one, then go back to the Part set, then activate another etc. Is this intentional? If it is intentional what is the purpose for not loading all the parts when I open the file? If not intentional, is this an easy issue to fix?