Adding New Tracks by Double-Clicking in the Edit or Mix Windows
Pro Tools lets you add new tracks by double-clicking in blank space below tracks in the Edit window or below or to the right of tracks in the Mix window.
To add a new track of the same type and channel width as the last new track, do one of the following:
Double-click in the empty area of the Mix window below or to the right of any current tracks.
Double-click in the empty area of the Edit window below any current tracks.
If no tracks exist in the project, a stereo audio track is created by default.