Version: (using KDE Devel) Installed from: Compiled sources Compiler: gcc 3.2.1 OS: Linux Sometimes (it seems to happen sporadically), KMail forgets that it's supposed to be in the system tray. The setting itself is still set in the Network settings, but the icon doesn't show up when starting KMail (I have the system tray set to always on). In order to make the icon appear, I have to go into the settings, uncheck the "System tray notification" box, click Apply, check it again, and click OK.
Thanks for your report, Joshua, are you still seeing this with kmail 1.5.2 or later?
It's been quite some time since I actually ran KMail in a KDE environment, so I haven't been using the system tray icon. (I've also gone back to a stable KDE, instead of CVS, as I just didn't have time to bughunt anymore.) Sorry I can't help you any more here.
Closing, as I can't reproduce it here.