And neither do the enemys.
It's my first game, small system vs 1 AI. My ships and defenses were all doing their job defending while I built up and captured half a dozen planets. So with a decent fleet I go in big and attack a well defended enemy planet.
As soon as they arrive all ships are swarming everywhere, just like in a battle.
But nobody is shooting.
Radius set to gravity well - check. Auto attack - check. At war with ebemy - check
Manually targeting, I get a 'yes captain!' response, they move into position near the new target... and just sit there.
So I leave it an hour, still ships flying around everywhere, deploying special powers, laying missile platforms, etc. But not a shot has been fired, not a ship lost or damaged.
And now, when an enemy ship enters MY system, the defenses just sit there and let them by. All was fine til I made my first attack on the enemy planet, now my ships are neutered... 
Please help - what the heck am I doing wrong?