Linking and Unlinking Layers
If you're currently looking at the Layers palette, and wondered where the linking button is, don't worry; it's not missing, it's just been moved. Linking multiple layers is a snap, simply select one or more layers and then click the Link Layers button (

Link Layers
Open a multiple layered document.
Select the Layers palette.
Select two or more layers.
Click the Link Layers button, located at the bottom of the Layers palette.The selected layers are now linked. A link icon appears next to the linked layers.
Unlink Layers
Open a multiple layered document that contains links.
Select the Layers palette.
Select a layer that contains the link icon.TIMESAVER
To unlink several linked layers, select them before continuing.Click the Link Layers button, located at the bottom of the Layers palette.TIMESAVER
To temporarily disable a linked layer, Shift+click the link icon for the linked. A red X appears. Shift+click the link icon to enable it.