Dissapearing Shaders

[Kengo]

For some reason a lot of system shaders like caulk and trigger seem to have just dissapeared. I can get them from a previous map then use them in new maps...but they aren't displayed as being there, just as those blue and black squares that indicate the shader isn't to be found. They work within levels I think, just not in the editor, and it makes things a bit confusing.

 

I got a feeling fiddling around with custom textures might be the problem. Any ideas anyone, is it something that is missing, something I've moved, is there a configuration I should change? Any help appreciated.