For some reason, once a custom swatch library is defined, we can't edit it. An icon showing a pencil with a line through it indicates that. But why can't we make the swatch library editable (temporarily), e.,g. by alt-clicking the icon, or right mouse button it?

This is so rigid and inconvenient.

Also make it possible to save a swatch group as a new library, in stead of saving all in a newly created library. It's quite impossible to create a library from a subset of swatches currently.