Prime User Function Catalog, Pressing "Run"

[goetz]

From what I have seen for CAS user functions so far, the programs in the program editor are only used to store a program into a CAS program variable. You can indeed remove the program from the editor/list and the user defined CAS function remains in the CAS variable (under Vars->CAS->Program).

To update, you can edit the existing program in the program editor and hit the "Check" button. This should then update the CAS program variable. If you rename the function in the program editor, you should get a new copy in the new CAS variable.

This is based only on my observations. For the question why it was decided to be designed and implemented that way and for more details, I would have to refer to the HP prime developer team.