The layer controls are controls that can be added, removed and moved around to determine what layers go to make up the contents of a plot. You can have zero, one or several of each. Which ones are available is dependent on which plot type you are using (for instance the Function control is only available for the Plane plot). Add instances of each control to the control stack by using the entries in the plot window Layers menu, or the corresponding toolbar button.
The available layer controls are described in the following subsections. At present there are only two of them, and one of those is only available for the Plane plot. More may become available in future releases.