Apple Final Cut Express 4 - Manual (Page 351)

Chapter 24 Working with Tracks in the Timeline 351
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To move the static region up or down in the Timeline:
m Drag the center slider in the static region’s scroll bar to move the entire region,
automatically resizing the scrollable regions above and below the static region.
To eliminate tracks from the static region, do one of the following:
m To eliminate video tracks from the static region: Drag the upper thumb tab of the static
region down so that it overlaps the lower one, then release the mouse button.
m To eliminate audio tracks from the static region: Drag the lower thumb tab of the static
region up so that it overlaps the upper one, then release the mouse button.
Drag the center slider
to move the static region.
To eliminate audio tracks,
drag this thumb tab up.