Locking is useful for preventing accidental changes to a layer. A locked layer displays a crossed-out pencil icon in the Layers panel. Objects on locked layers cannot be selected or edited directly; however, if objects on locked layers have attributes that can be edited indirectly, they will change. For example, if you edit a tint swatch, objects on locked layers using that tint swatch will reflect the change. Similarly, putting a series of threaded text frames on both locked and unlocked layers will not prevent text on locked layers from recomposing.