Lets you select a layer by clicking its paint.
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 - 1. The default value is 0.25.
On – You can pick image layers. You cannot pick shape layers.
Off – You can pick image layers or shape layers.
On – You can pick image layers. You cannot pick text layers.
Off – You can pick image layers or text layers.