Node is locked, can't change value!Help!

Like this,anyone know how to Unlock?

It looks like your node setup may be linked from another file. If you want it to be fully editable, you’ll need to break the link by making it a local copy. Check out the manual page for Make Local here:

Thank you! I follow manual Object ‣ Relations ‣ Make Local but not work.

I notice manual say " Known Limitations-For the most part linking data will work as expected, however, there are some corner cases which are not supported."

Maybe this is the Limitations,Probably because it was downloaded from blender cloud and packaged at the beginning.