Edit Modes and Tools : Zoomer Tool : Continuous Zoom with the Zoomer Tool
 
Continuous Zoom with the Zoomer Tool
Use the Zoomer tool to zoom in or out continuously.
To use continuous zoom on one track or a group of tracks:
1. Select the Zoomer tool.
2. Hold the Control (Mac) or Start key (Windows) and do one of the following:
*Drag to the right to continuously zoom in horizontally.
*Drag to the left to continuously zoom out horizontally.
For horizontal zoom, all tracks zoom together. Tracks will zoom in or out centered horizontally on the location where you click.