Invisibility is broken when the attack starts instead of when it ends
In vanilla invisibility is voided when an attack is actually made instead of when you draw back for one. The unintended consequence of doing it on drawing back is that, if you juggle mouse buttons just right you can get in & out of your inventory with the attack still readied. So you stand around the corner from a room full of baddies, get your attack ready and then equip a CE invisibility item (it may take a few tries, but you can do this without releasing the attack), go in, 1-shot somebody without breaking invisibility, back out around the corner, rinse, lather, repeat until, 1-by-1, an entire room full of foes have been dispatched without any aggro.
Edited by Alexei Kotov