Doing a Google search for, "star trek online any way for sound to not lose focus", I found this thread.
This "feature" is very annoying since it lacks the option given to the player to turn it off or on, like other games I have played (Firefall has this option to turn off sound when the game window loses focus).
One of the reasons I find it annoying is that when streaming, it is very obvious you are losing focus to viewers of the live stream or if you are recording for YouTube. You just suddenly lose all sound.
It seems PWE/Cryptic developers didn't think of this or don't care. It is like this in Neverwinter as well (stupid mouse hostage there too...don't get me started on having to bring up a window in order to move my mouse off the game).
How about it devs? Do players have to wait another 2 1/2 years for this to be put in across all your games?