Found in the maunual (aparantly every Copy of vegas comes with one)
Doing a search on "Fade to Color" I found
Hide envelopes
From the View menu, choose Video Envelopes and select the envelope you want to hide.
Hiding an envelope simply removes the line from the timeline while retaining playback properties.
Actually, you don't need the manual. Using the search function in help which is found in every install of the application, typing in "envelopes" will show you everything that is in the manual and more. It even will do some things for you, similar to an Intelligent Assistant.
Zippy, I'm proud of you.. keep posting like this and you'll get better answers and everybody will learn more.
You can have a menu button to show and hide volume and pan envelopes.. but that's not what you want (I know). I always use the scroll mouse buton to zoom in quickly to the end of an event so I can't click the wrong button there..