The visible note range in a MIDI track can be controlled in two principle ways: the note scroomer, or the scroll wheel of your mouse.
The default note range shown in new MIDI tracks is controllable in Edit > Preferences > MIDI
The scroomer offers two kinds of control.
"Grab" the in the middle and move it up or down - this adjusts the absolute note range displayed up or down.
"Grab" the top or bottom handle of the scroomer, and move that up or down - this adjusts the extent of the note range displayed.
While in internal edit mode (used for editing MIDI), several scroll operations can be used to control the visible note range: