interactive markers does not work with gmapping_demo

edit

After comparing the configuration files in /turtlebot_rviz_launchers/rviz

I found what seems to be a solution. When you run

roslaunch turtlebot_rviz_launchers view_navigation.launch

It uses a configuration file navigation.rviz, if you compare that to the file used by

roslaunch turtlebot_rviz_launchers view_robot.launch

which is robot.rviz, you see that robot.rviz has lines in it to add the class rviz/InteractiveMarkers, evidently you can not simply add interactive markers from rviz gui, it must be declared in the configuration file first. The file navigation.rviz did not have these lines so I added them:

- Class: rviz/InteractiveMarkers
  Enabled: false
  Name: InteractiveMarkers
  Show Axes: false
  Show Descriptions: true
  Show Visual Aids: false
  Update Topic: /turtlebot_marker_server/update
  Value: false

Once I did this and launched rviz again with above commands, the interactive marker was in rviz and when I clicked on the interactive button, I could navigate using interactive markers while mapping was taking place. Of course you still have to run

roslaunch turtlebot_interactive_markers interactive_markers.launch --screen

I do not really understand the syntax in the *.rviz files. I could attach my modified navigation.rviz so others can do a diff and see where I changed it, but I don't have enough points. Maybe someone can tell me if what I did is the correct way to fix this issue or not.