Hello Simon,
Quoting you: "You can't copy between different library files"
And now: "I am trying to copy symbol graphics between two parts so it's actually within the same file."
I am unsure what you are trying to accomplish.
I'm sure I can help, but I'm usure what your goal is.
It would be much more productive with more words aimed at explaining the goal, than expressing your dismay toward learning a new tool.
I would tend to assume you have two libs, and want to copy the "graphic" symbol or sections of it toward a new part in another lib.
Once you selected the part, you can easily select the graphic symbol, and CTRL-C (or right-click and copy), then create a new part in another file (or select an existing part) and paste there...
Just tried it, it works.
Also, trivia: you are correct: CS is based of AD, wich is itself based of AD for DOS.
https://en.wikipedia.org/wiki/Autotraxhttp://airborn.com.au/layout/autotrax.html