Understand the order of graph's entities

Here the relevant section of my configuration file:

history_graph:
  gr1:
    name: Temperature
    entities:
      - sensor.dark_sky_temperature
      - sensor.femtoth1_temperature
    hours_to_show: 96
    refresh: 60

  gr2:
    name: Humidity
    entities:
      - sensor.dark_sky_humidity
      - sensor.femtoth1_humidity
    hours_to_show: 96
    refresh: 60

So I want as first entity in both graphs the dark sky sensor, them the one called femtoth1. But as you can see in the screenshot below the first one has the entities swapped.

What’s my error here?