If you add multiple command lines at a certain point, they are treated as a "block" i.e., you are able to move, copy, or delete only the whole block of command lines.

You can specify only one CL command at the beginning or end of the tool path (it can have multiple lines). Therefore, if you repeatedly try to select the Beginning or End option, a message informs you that a command already exists at this location, and you can modify it. Use the Command option in the MODIFY CMD menu to add the appropriate lines to the existing CL command, as described below.