Currently, there is no obvious indication of the medium contained within airflow or mesh tiles. Current behavior is shown for water, hydrogen and vacuum media. I believe this leads to confusion about the mechanics of how airflow and mesh tiles actually work. The tooltips make them appear as if they are ordinary tiles with ordinary tile properties, but many of the physics of the tile are actually the physics of the medium contained within. Currently, you must click to cycle through to the unlisted medium contained within. A bit less friendly than a tooltip. Solution: display the medium contained within the tile in the tooltip list.