How do I permanently delete a contact from my Yahoo Messenger?

I have a contact on my Messenger List that signs in and out constantly... The Messenger window flies open and this is very distracting. I prefer to be notified when my friends enter or leave Yahoo Messenger. I just want to remove one contact. And know how to do so in the future if someone else becomes annoying. I have deleted the contact's information, and removed the contact from my list. However, every time this contact enters and leaves I am still notified. Help!|||Go to Preferences, Ignore List, check on-Ignore anyone who is not on my Messenger list, or type in their name on Ignore list.|||put them in your "Ignore List" if it still pops up after deleting the contact in your messenger list.