Version: (using KDE KDE 3.4.2) Installed from: SuSE RPMs OS: Linux if I set double click in mouse settings as default in kde control center this should be honored by KMail, too. If I do for example a single mouse click on an attachment, this is being opened, which should not happen. Unfortunately many KDE applications don't honor this setting, this should maybe be fixed in other applications, too. For people switching from Windows to KDE it is very confusing if they expect double click behaviour, even more confusing if you set the system to double click behaviour and some applications ignore it.
You don't double click links in a web browser.
As already said, links in HTML (kmail displays attachments link in the message as HTML) are never double clicked - also not on windows.