Seeing the invisible in World Editor? [SOLVED]

I have created an invisble ramp to help my characters get smoothly over minor ledges. I can now get my AI characters to successfully negotiate kerbs, etc.

The only problem is, now I can't see my invisible ramp (which I know was the point). But I now want to copy & paste further examples, and I'd like to see them as I place them, and then make them invisible.

So is there a quick way of (temporarily) making visible materials that have been made invisible (other than editting the material - which is possible, but quite a few mouse button presses).

Basically I'm looking for a short cut to save wear & tear on my fingers.

Edit: I'm just resorting to turning the transparant on & off in the material - now I'e got used to it is seems quite quick.