Command entry:Track View Dope Sheet Introduction Right-click the blank area of the toolbar to the right of Modify Child Keys. Show Toolbars Extras : Dope Sheet
Provides extra tools for use in Dope Sheet mode.
Interface
Exclude Left End Point
Prevents a key at the first frame of a selected block of time from being copied to the clipboard.
Exclude Right End Point
Prevents a key at the last frame of a selected block of time from being copied to the clipboard.
Command entry: Track View 
Dope Sheet Introduction 
Exclude Left End Point
Exclude Right End Point