I just wanted to let you know that after different people starting discussions on the subject for several months now, we have settled on a new mouse behavior in the contact list. Single click now selects a contact and double click opens a chat window.
The big debate was coming from the fact that we are now supporting some of the most popular IM protocols and along with that we aim to remain a VoIP client. So the question was what is the most appropriate selection policy in such a client. The single-click-opens-a-chat-window behavior (which is the one we had till now) is very handy for people using mainly instant messaging, but is not at all appropriate when someone wants to call. Furthermore it could be very annoying if one clicks on a contact with the intention to call him and each time a chat window pops up. This argument almost answered the question and gave to single click the role of a simple select.
The second question was whether we use the double click to open a chat window or to call someone. Symphorien gave a good argument in favor of using the "double click" for opening a chat window and it was that we have already a big, visible, easy to access button to make a call and we would like that the IM stays very accessible too.
Thanks to Symphorien, who implemented this new behavior, along with the drag&drop functionality in the contact list!
For people who got used with the old policy, excuse us for this inconvenience! Hope you will understand our reasons.