There are options for rank lists in the panel called "Rank List" just above the main expression display.

You can’t rank by p-value in the current version of the GXB. However, you can rank by fold change, difference value, or both.

The GXB is optimized for screens 1024px wide or larger; it will still be viewable on smaller screens, but you will have less of an overview. You have the option of hiding either the Gene List panel, or the information tabs, or both in order to let the graph take up a larger percentage of the screen.

When you have selected at least one overlay option, you may click the Overlay Legend Button; a key to the overlays will become visible. You can also choose to download the key as an image.