can't find info on 3D viewport rendering adjustments (renderlayers)

Hi. How much control do I have over the cycles/rendered setting in the viewport? Changing the renderlayer options does nothing and neither does the ‘preview active layer in viewport’ button. I can’t even get a search hit nor find info in the manual on this subject.

thanks

Viewport rendering shows the currently visible objects in the currently visible viewport layers. Render layers are used by the compositor, not the viewport.

and neither does the ‘preview active layer in viewport’ button.
It does for me. It shows the layers as indicated in the selected renderlayer settings

Cycles render layers are not like Maya and Max’s where you can change material colors and basically reset anything you want per render layer which I wish you could.

You can create new scenes up at the top though.