The Layer List widget provides a list of 2D or 3D layers in the scene.
Configure the Layer List widget
There is no configuration for the Layer List widget.
This widget can be set to open automatically when
an app starts. Hover over the widget and click the Do not open this widget when
the app starts button 
to change the setting to Open this widget automatically when the app starts. (For widgets that you need to add to the app first, you can turn on this option after configuring the widget.)
Use the Layer List widget
To use the Layer List widget, do the following:
- Click the Layer List widget to open it.
- Check the boxes to turn layers on and off in the scene.
- Optionally, hover over the layer and click the Go to full extent button to zoom the scene to the layer's full extent.