Two possible reasons for this are:
(1) You can only add static activities to stationary locations, and you can only add mobile or haul activities to Route Segments. So NoiseMap only shows the permissible activities in the drop-down list. Use the activity manager to check or change the type of activity. Beware that NoiseMap offers Mobile as the default.
(2) You can only add an activity once to a working location. Once you have added a particular activity, it will no longer appear in the drop-down for that location, but it will be available for you to add to other locations.
