Reset_Composition_Work_Area.jsx

/**
 * @name Reset Composition Work Area
 * @version 2.1
 * @author Kyle Martinez <www.kyle-martinez.com>
 *
 * @description Set the Work Area to cover the entire composition.
 *
 * @license This script is provided "as is," without warranty of any kind, expressed or implied. In
 * no event shall the author be held liable for any damages arising in any way from the use of this
 * script.
 *
 * I'm just trying to help make life as an After Effects animator a little easier.
 */

(function resetCompositionWorkArea() {
    app.beginUndoGroup("Reset Composition Work Area");
    var comp = app.project.activeItem;
    comp.workAreaStart = 0;
    comp.workAreaDuration = comp.duration;
    app.endUndoGroup();
})();