I've been reading this forum for awhile now and finally decided to chime in...So here is the ringing. :']
After you use the Eye on a character in your party and get the evil eye trait you can place the evil eye in the wall socket (to open the door to get unboogred). After opening the door, if you click on the eye again you can retrieve it from the wall socket and the eye is recharged and ready to give the Evil Eye trait to another character. I gave all my characters the evil eye trait this way...Don't know if this will stop them from learning other traits or not, but we'll see.
To use the Evil Eye trait you click on the button on the main screen that normally shows the picture of the dragon head...with the Evil Eye trait learned this changes to a picture of an eye.
On an unrelated note, after reading the board today I realize that I'm not going to become an assassin, since I killed the guy that is suppose to teach that to me...WHUPS!...Now to figure out how to win the Bronze beast quest from the mayor of Ishad'Nha....

HO HO! After saying that I needed a way to shut off that Bronze firebeast, I come across this highly sophisticated thing called "Search" . It seems that when you need help on something you can actually type in what you want instead of going page by page down the message threads hoping that somebody put pertinent information in the Subject line. Yea gods! When I was trying not to get toasted like a marshmellow I overlooked a switch to turn off the fire beast..Time to head back to the dragon spire. :]

evil eye will not stop you learning other traits. You should consider changing class to a bard as the duelling banjo is pretty deadly.