Tool Palettes Paint > Pick Layer by Color > Pick Layer by Color Options

Paint > Pick Layer by Color

Lets you select a layer by clicking on its paint.

To select a layer by clicking on its paint

Do one of the following:
With any brush active, press and hold the Z key.
Choose Paint > Pick Layer By Color .
Click the paint of the layer you want to select.

Pick Layer by Color Options

OpacityThreshold

The opacity that a pixel of paint must have in order for the Pick Layer By Color to select its layer. The valid range is 0 to 1. The default value is 0.25.

Ignore Shape Layers

On-You can pick image layers. You cannot pick shape layers.

Off-You can pick image layers or shape layers.