A layout option is a customization point for the layout algorithms, with a specific data type and optionally a default value, used to affect how the active layout algorithm computes concrete coordinates for the graph elements.
User-configurable layout options for a particular diagram object can be viewed and configured through the Layout View.The Layout View can be opened from the context menu of a selected diagram object by clicking the Show Layout View entry.
On opening the layout view, and selecting any layout option, a description of the layout option is available in the footer of eclipse SDK. This is shown below: