Hi Samuel,
When the library link is disabled for a block that comes from a library model (using “Library Link > Disable Link” or “Set Link Status > Disabled”), the entire block and its contents including any subsystems becomes editable. As a result, the library link option appears greyed out for the subsystem. To remove the link, you can use the break link option.
Please refer to this documentation about break and disable library link: https://www.mathworks.com/help/simulink/ug/disable-links-to-library-blocks.html
Hope this helps!
