MIDI : MIDI Editors : MIDI Editor Window Toolbar : Scrolling Submenu

Scrolling Submenu
The Scrolling submenu lets you select the scrolling options for the MIDI Editor window independently of other MIDI Editor windows and the Edit window. The scrolling options include:
No Scrolling
The MIDI Editor window does not scroll during or after playback. The playback cursor moves across the MIDI Editor window, indicating the playback location.
After Playback
The playback cursor moves across the MIDI Editor window, indicating the playback location. When playback has stopped, the MIDI Editor window scrolls to the final playback location.
Page
The playback cursor moves across the MIDI Editor window, indicating the playback location. When the right edge of the MIDI Editor window is reached, its entire contents are scrolled, and the playback cursor continues moving from the left edge of the window.
Continuous
The MIDI Editor window scrolls continuously past the playback cursor, which remains in the center of the window. With this option, playback is always based on the Timeline selection (unlike the Center Playhead Scrolling option).
Center Playhead (Pro Tools HD Only)
The MIDI Editor window scrolls continuously past the Playhead, which is represented as a blue line in the center of the window (or a red line when recording).
Follow Edit Window
When selected, the MIDI Editor window follows the scrolling option selected for the Edit window (Options > Edit Window Scrolling).