Editing : Edit Modes and Tools : Edit Modes

Edit Modes
Pro Tools has four Edit modes: Shuffle, Spot, Slip, and Grid. Grid mode provides two modes of operation, Relative and Absolute, explained below. The Edit mode is selected by clicking the corresponding button in the upper left of the Edit window.
 
The Edit mode affects the movement and placement of audio and MIDI clips (and MIDI notes), how commands like Copy and Paste function, and also how the various Edit tools (Trim, Selector, Grabber, and Pencil tools) work.