Mari 4.5v2 docs:

Shaders Palette

The Shaders palette and the controls that can be found on it are described in the table below. When controls also bring up additional dialogs, these are referenced for more information.

What It Does

The Shaders palette displays the lighting shaders and allows you to toggle between the shader setup for the current channel, layer stack, layer, and paint target, as well as custom-made shaders.

Shaders Palette Fields

Control	Type	What it does	Dialog	Notes
Current Channel	shader	Default shader that displays only the paint in the selected channel.		This shader can also be found on the Project Controls toolbar.
Current Layer and Below	shader	Default shader that displays only the paint in your selected sub-stack (such as a mask or adjustment stack) up to the selected layer. If you don’t have a sub-stack selected, it shows the parent stack up to the selected layer.		This shader can also be found on the Project Controls toolbar.
Current Layer	shader	Default shader that displays only the paintable paint and masks in your selected layer.		This shader can also be found on the Project Controls toolbar.
Current Paint Target	shader	Default shader that displays only the paint in your selected layer, including any mask or mask stack, adjustment, filter or groups associated with the layer.		This shader can also be found on the Project Controls toolbar.
	button	Adds a new shader or layered shader to the shader list in the palette from a dropdown menu list of: • Unreal, • Principled BRDF, • VRayMtl, • Layered, and • Choose Diffuse And Specular.	Create Shader Dialog when selecting Choose Diffuse and Specular. Masks Formats Dialog when selecting Layered.	The Choose Diffuse and Specular option allows you to create a custom shader. Refer to the Create Shader Dialog for more information. The Layered option creates a layered shader. When selected, its layers can be accessed using the Shader Layers Tab Fields.
	button	Makes a copy of the selected shader.
	button	Removes the shader from the shader list in the palette.		Default shaders cannot be removed from the Shaders palette.
	button	Selects the default Current Channel shader from the shader list and displays only the paint in the current channel.
	button	Selects the default Current Layer and Below shader from the shader list and displays only the paint in the current layer stack.
	button	Selects the default Current Layer shader from the shader list and displays only the paint in the current layer.
	button	Selects the default Current Paint Target shader from the shader list and displays only the paint of the currently selected target.