I've seen this a couple of times but it's one of those things where figuring out exactly what led up to it involves a bit of guesswork.
What I think happens is:
I finish a tactical battle with the info space at the bottom of the screen minimised (using the little down-arrow at the left of the screen). I've minimised the info so I can better see the action and the game ends after I've clicked "End Turn" either through missiles already launched and running impacting their target or through the last AI ship destroying itself by triggering not-yet-fired weaponry on my ships.
In the next tactical battle, the info space no longer works as intended. In particular, the weapon loadouts of each ship do not appear in the centre of the screen either when I mouse over a ship or when I select one intending to engage with it. I cannot select weapons, switch off weapons or carry out any of the functions normally executed through that central portion of the info space.
Interestingly, it all seems to be fixed by saving the game and exiting and restarting the program so it's not a game-breaker (and it's probably pointless sending a savegame?) but it probably isn't WAI.