Tracks : Edit Window Views : Volume Indicator : Pan Slider
 
Pan Slider
The Pan slider controls the balance of a track between the assigned output pair. It only appears if you are using stereo tracks or mono tracks routed to a stereo output.
The Pan slider on a MIDI track is effective only if you are controlling a sound module that supports MIDI panning.
*Send Pan controls can be linked to the Main Pan controls of a track by enabling the Follow Main Pan button in Send window.