I have a relatively new EVO 4G, and I've noticed that for some reason trying to chat with a contact using Talk and Quick Contacts doesn't work. When I pop up the Quick Contact for a person who's online, I see a second dialer icon. When I press that, it gives me the option to use various chat methods, including Talk (and Skype). However, when I choose Talk, it asks me to "Complete action using" and gives me a huge list of things, but none of which are Talk. Any ideas?