In addition to the Zoom controls in the Toolbar, Pro Tools provides horizontal and vertical zoom buttons in the lower-right corner of MIDI Editor windows.Zoom the lane heights proportionally for Automation and Controller lanes.Zoom the Timeline just like the Horizontal Zoom controls in the MIDI Editor window toolbar.
Pro Tools provides MIDI Zoom In and Out buttons in the upper-right corner of MIDI Editor windows. These controls function exactly the same as the MIDI Zoom controls in the toolbar, and let you zoom in and out vertically on MIDI notes.