Ignore Animation Range allows a parametric, non-keyable controller track to be active throughout the entire length of the animation, independent of the track's current animation range. Choosing this option changes the track's background color to purple.
This setting is active by default on all new controller tracks (turn off the Override Parametric Controller Range By Default option in the Animation Preferences to change it). However, controller tracks from older scenes are set to Respect Animation Range to maintain their original behavior.
Example: To set a controller track to ignore the animation range:
Motion Panel
Assign Controller rollout, highlight the sphere's Position track.
(Assign Controller), and then choose Noise Position from the Assign Controller dialog.
Select the sphere, and then right-click it. From the quad menu, choose Dope Sheet.

Play the animation.
Because Ignore Animation Range is on by default, the sphere moves randomly even before entering the track's animation range.