Running linphone in Ubuntu Studio (xfce). When starting linphone an icon appears in the notification area, right-click this icon and choose quit is one way to quit linphone. I wouldn't consider the behaviour as a bug. Skype on Windows has the same behaviour, cosing the Skype-window with the close-button will not stop Skype. I think it's intended behaviour.
Running linphone in Ubuntu Studio (xfce). When starting linphone an icon appears in the notification area, right-click this icon and choose quit is one way to quit linphone. I wouldn't consider the behaviour as a bug. Skype on Windows has the same behaviour, cosing the Skype-window with the close-button will not stop Skype. I think it's intended behaviour.