Tracks Disappeared

Hello,

I was working on a project with 20 different tracks. I zoomed into 1 to edit but when I zoom out, all the other tracks have disappeared, and I can only see the one I just edited.

The other tracks are still paying in the background, so they are there... how can I see them again? It's driving me nuts!

Thanks.

From the manual.

My waveforms are gone, but I still hear audio; it
says Busy in the corner of the clip
If your audio clips are labeled “Busy”, the waveform display has not finished drawing yet, or may be
corrupt. To force SONAR to redraw waveforms in the current project, perform the following steps:
1. Go to Edit > Select > All to select all clips.
2. On the Track view Clips menu, select Recompute Picture Cache.
If you still have trouble with waveform redrawing, please see “Optimized picture cache redrawing” on
page 1131.