The way to toggle "cursor navigation" On/Off is to goto the settings page by pressing the activity icon (which is between device-left & device-overview button). In the second settings page, you can enable/disable cursor-navigation.
Another adv. of cursor-navigation mode is as follows: When u r in cursor-navigation mode, the cursor keys are used to naigate between pages and devices. If you press the Navigation toggle button which is below the firm key 1, cursor navigation is temporarily turned-off and you can perform all the actions that are specified under the cursor keys. we can press the toggle button again to return to navigation mode.