According to the spell Invisibility when you make an attack (spell or otherwise) that has the potential to deal damage to a creature the spell breaks making you visible.
The dancing weapon property states "As a standard action, a dancing weapon can be loosed to attack on its own"
I interpret that to mean that since the weapon is no longer in my position (though it is still in my square) and it is making attacks on it's own the my Invisibility will not be broken as I'm not the one who is making the attack. But I'm not sure about my reading of it. How would you rule it?
I concur.
When you're invisible, you can summon a monster and then the monster can attack - this does not break invisibility. Mechanically, I don't see any difference between releasing a dancing sword to attack on its own and summoning a monster to attack on its own.
Cool thanks for the help guy(s) and gal(s). I have an idea for a new PC that's going to be rather fun with this addition.
Just keep in mind that as soon as the sword leaves your possession it becomes visible, so its first attack wouldn't benefit from Invisibility.
You could, however, cast invisibility on the sword itself before loosening it to get the same effect.