Ok .. nothing special found on the shader code, maybe Ashley can help.
It's not working for me too, dont know why ?
So how i preview shaders not showed in C2 editor when i am working on ?
I have Chrome, and firefox nightly; when shader running open web console or dev tool on chrome(install shader editor).
After this click on shader editor tab, and edit shader like you want. If the picture become invisible refresh screen with mouse
in scaling Horizontaly tool window. Now you can see modifyed shader..