I think the Xenon Theme music is one of the best parts of the Xenon U.I. or it's Redux. It's very chill compared to the regular theme which I initially found as jarring, despite it's part of the vanilla game as the official theme tune. I had pigeon holed the original music as that what you might have for an scifi tv series or a spoof of one. However the Xenon version is low key, very relaxing...
Maybe it is not the fault of an OXP this time. Does the game appear to be not responding before the music cuts off? Do you happen to click something that causes a pause in the main window, like the top left window icon (assuming you run on Windows, this would open the system menu for the window) for example? If the game loop is not updating, the music buffers will be exhausted after a few seconds and the music will stop. Note that loading a save file can also result in the music stopping because the game loop is suspended while loading happens.
If nothing like this happens and the music still cuts off, it could be a problem with something (that could also be an OXP) causing a temporary halt of the game update loop, just about long enough to cause the music buffers to run out of data. Not sure which OXP would be in position to cause this though, it is a bit extreme to be honest.
Also, as a general advice to all, you need to remember that OXPs do consume system resources. Enabling a bunch of them in one go is never a good idea, there is always a cost in resources for each OXP you add. I see a lot of people recently running 300 or 400 OXPs or even more - this is nuts, Oolite was never meant to carry this kind of load all at once! Add expansions one at a time and before you do think if you really want or need the OXP you are adding. It is best to have a general idea what you want your game to contain and then go look for it.
You know, in almost 5 years of reading through threads and the wiki I’ve never come across this “too many OXPs” warning before. Not to say it does not make sense - even in Cim’s day the number was a fraction of what we have now…