I'm editing a video with two video and two audio tracks. On one of the audio tracks, the Mute button is now combined with the Automation Settings button and is greyed out, so I can't mute the track. This is on only one of the audio tracks. The other audio track and both video tracks have a functioning Mute button and separate Automation Settings button. I must have accidentally bumped something with my elbow...but what is a mystery as neither the Help file nor the Vegas manual nor any descriptive search string I enter on Google has come up with a way to change this back to normal.