I want to add some more info.

Yesterday I have logged out the operator client after a full day of work and I wrote down all the IP of the visitors visitors "visiting" our web site since 9 hours. This morning I have logged in again (so after 12 hours) and some of the visitors are still there, connected since 21 hours, it is unrealistic, isn't it?

 

Please try to fix this bug, it is really annoying and makes the visitors list useless.