Probably I misunderstand something: This Advanced Condition
Does it mean that something only happens if the dock is shown? Probably not, because it does not works. 
Then asked differently, how can I make something happen only if the dock is shown/visible? Thanks!
This is most likely just some custom variable that some preset in BTT has defined for you.
I think you could use this condition to only trigger if the dock window is visible:
visible_window_list CONTAINS "Dock - Dock"
Yes, this works perfectly, thank you very much!
Ah, sorry Andreas. This works as it should
But what is the opposite? Probably "does not contain". But that does not exist. And with "is not" it does not work.
Choose the None selector instead of the "All" selector on the top left 
lol ... of course, did I already mention that formal logic is not my strength? Danke 
