Different "window" icons - but why?

  • Platform information:
    • Hardware: RPI4, 8GB
    • openHAB version: 3.0.2

I am using door/window contacts to visualize open/close states of windows. All of them are configured in the same way as “item”, “group”, “equipment” of category “window”. When I add the item into a list-view and use “oh:window” as icon, some of the windows are grey, others are blue:

Bildschirmfoto 2021-06-14 um 11.41.35

How do I have to change the configuration so they are all represented by the blue window icon?