it happens while the song is playing.
the line that normally moves along left to right just goes away. dragging the bar at the top up/down fixes it. still annoying.
anyone else see this?
 

I had it disappear once when I opened an older project. I closed the project and reopened / saved and the problem has not reoccurred.

It disappeared on me once too right before a pretty bad crash (had to force close Sonar). I wasn't even doing anything weird. I had been cutting MIDI drum takes, same thing over and over again for a half hour or so (do a take, listen back, do a take, listen back...), and all of a sudden when listening back the timeline disappeared for a few seconds but the song still played... then freeze... whitescreen... no response... wouldn't close normally. So I force closed it, reopened the project and everything was fine. Totally random and I kept doing the exact same thing for another half hour with no issues. I have no idea why it did that.

sounds like http://forum.cakewalk.com/fb.ashx?m=2673327