Hi,
I pressed refresh button, but some shaders don't refresh. And “Update Shader Ball Icon” RMB menu item is grey. Is it by design or bug?
Thanks!

Any one knows?

I have the same problem.

There is also the “Shader View” update problem which is not working anymore, I know a lot of people don't use it like me but for people that are coming for other packages is very useful.

It's probably a bug (I just logged it as 73280).

A handful of gallery materials can't use a standard ball to illustrate their effects. This is applicable mainly to volume materials (smoke and fire). They use pre-rendered icon for use in the gallery.

Somehow, the Principled Shader gallery entry also claims it's not re-renderable, which is a bug. Especially that Principled Shader SHOP works fine.