Your comments

The compile shader button is always like that when you've got real-time node previews on.

As for the panner, your texture is probably just set to clamp instead of wrap in the texture import settings :)

It could be that you have multiple custom material or shader inspectors in your project

That's super odd, I'm actually not sure what could be causing this :(

Try the full reinstall anyhow, sometimes it can break anyway. Don't forget the layout reset!

SF 1.26 is 5.3+ only, you'll need to reinstall the latest compatible version! Here's a clean install guide: http://acegikmo.com/shaderforge/faq/?Q=erroronnewversion#erroronnewversion
In addition, make sure you download SF through the asset store *inside Unity itself* to make sure you get the correct version

Seems like you might have the wrong version of SF for your current version of Unity. Try deleting SF and then updating through the asset store inside Unity, and then install again.

More details on a fresh reinstall: http://acegikmo.com/shaderforge/faq/?Q=erroronnewversion#erroronnewversion