code: function _initNavigationCommands() {
          CommandManager.register(Strings.CMD_NAVIGATE_BACKWARD, NAVIGATION_JUMP_BACK, _navigateBack);
          CommandManager.register(Strings.CMD_NAVIGATE_FORWARD, NAVIGATION_JUMP_FWD, _navigateForward);
          commandJumpBack = CommandManager.get(NAVIGATION_JUMP_BACK);
          commandJumpFwd = CommandManager.get(NAVIGATION_JUMP_FWD);
          commandJumpBack.setEnabled(false);
          commandJumpFwd.setEnabled(false);
          KeyBindingManager.addBinding(NAVIGATION_JUMP_BACK, KeyboardPrefs[NAVIGATION_JUMP_BACK]);
          KeyBindingManager.addBinding(NAVIGATION_JUMP_FWD, KeyboardPrefs[NAVIGATION_JUMP_FWD]);
          _initNavigationMenuItems();
      }
docs: Function to initialize navigation commands and it's keyboard shortcuts.
  @private