I duplicated an object and then added an animation to one of them, the animation appears in both objects in the outliner, also in the dope sheet and graphic editor and I can't remove the animation from one of them without removing it from the other.
So, I removed all the key frames and the animation from the dope sheet and graph editor, also unlinked the animation in the outliner but the animation is still showing in the outliner and every time I try to ad a new one, it becomes shared by both objects again.