If you are unable to see the full market depth and/or traded volume figures in the right column (see top image)
But you have both options ticked in the setting menu (see bottom image)
Then the most likely reason is that Betfair has restricted the data your account can access, another sign of this is if you see erratic movement in your micro charts on your one-click screen. The most common reason for this restriction is if your account has no funds in which case just adding some funds usually resolves this automatically.
Other reasons may include if you have used practice mode for a period of time but without placing any live trades in which in which case you will need to contact Betfair directly by submitting a support ticket https://betfairdevelopersupport.zendesk ... quests/new for them to resolve.